If you're going for 1100s Western Europe, dining forks are right out. They are an affront to God and you will die of the plague.

Forks had been around for centuries, but those were big, two-pronged ones, used to hold meat in place while carving or for lifting food out of a cauldron. Around the 7th century, eating forks started to appear at the courts of the Byzantine Empire and the Middle East, and over the next three hundred years or so they took off among noble families in the region. They still weren't a European thing, though. In 1004, Maria Argyropoulina, the niece of the Byzantine Emperor, married the son of the Doge of Venice and used a fork at her wedding feast. People were shocked. It wasn't just weird, it was ludicrous and decadent, practically blasphemous. One of the local clergy argued that 'God in his wisdom has provided man with natural forks: his fingers. Therefore it is an insult to him to substitute artificial metal forks for them when eating.' When Maria Argyropoulina died a couple of years later of the plague, Saint Peter Damian announced that it was partly because of the fork thing:

Nor did she deign to touch her food with her fingers, but would command her eunuchs to cut it up into small pieces, which she would impale on a certain golden instrument with two prongs and thus carry to her mouth. . . . this woman’s vanity was hateful to Almighty God; and so, unmistakably, did He take his revenge. For He raised over her the sword of His divine justice, so that her whole body did putrefy and all her limbs began to wither.

In spite of the risk of putrefaction and withering, forks did very gradually take off in Italy. By 1533, when Catherine de Medici married Henry II and brought along a set in her dowry, they made it to France, although they took a while to stick. It took them even longer to reach England. They started with sucket forks, which were for eating sweetmeats in syrup - Henry VIII's inventory includes 'Item one spone wt sucket forke at thende and gilt poz one oz iii quarters'. These were the OG spork: they had two prongs at one end, for spearing something like plums in syrup, and a bowl at the other end for eating the syrup. The English didn't get into dining forks for a while after that. Thomas Coryate took the grand Tour of Europe in 1608 and wrote:

I observed a custome in all those Italian Cities and Townes through which I passed, that is not used in any other country that I saw in my travels . . . The Italian, and also most strangers that are commorant in Italy, doe alwaies, at their meales use a little forke when they cut the meate; for while with their knife, which they hold in one hand, they cut the meate out of the dish, they fasten their forke which they hold in their other hande, upon the same dish, so that whatsoever he be that sitteth in the company of any others at meate, should unadvisedly touch the dish of meate with his fingers, from which all at the table doe cut he will give occasion of offence unto the company as having transgressed the lawes of good manners . . . The reason of this their curiosity, is because the Italian cannot by any means endure to have his dish touched with fingers, seeing all men’s fingers are not alike cleane. Hereupon I myselfe thought good to imitate the Italian fashion by this forked cutting of meate, not only while I was in Italy, but also in Germany, and oftentimes in England, since I came home.

His English friends took the almighty piss out of him for his fancy new fork, to the point where he wound up with the nickname 'Furciferus' (Pitchfork).

So no forks for you. You don't have plates, either. Probably you each have a trencher, which in the 1100s would be a big round of hard-crusted stale bread. (Later they were made of wood.) Whatever you're eating - meat, vegetables, pottage - is served on a platter and gets dumped on top of the trencher. You use your hands, supplemented by a knife and/or spoon, to eat it. At the end of the meal, some (later) sources say the sauce-soaked trenchers were given to the poor as alms, but I don't recommend you try this.

You don't need to share a knife. Everyone brings their own.

On diet, I'm not much help because the twelfth century really isn't my zone. But the main defining factor isn't going to be your studenthood, but whether you're rich or poor. Students came from a fairly wide range of backgrounds. (Side note: some things never change. Students, rich and poor, were constantly writing home asking for more money. They mostly claimed it was because they needed to buy books, but historians, who have been students themselves, reckon it was for booze and partying.) I recommend you go for rich students, who would not only be able to afford much more interesting dishes, but would have servants - meaning they wouldn't be limited to just what they could be bothered cooking themselves. As a general rule, the richer you are, the more meat you eat - and you can have a wider variety of types of meat, and better cuts. The twelfth century is tricky because we don't have that many written records of daily life, but Charles Homer Haskins, in The Rise of Universities, describes the food section in the Dictionarius of John de Garlande, an early-thirteenth-century master at the University of Paris listing the things he saw for sale on the streets of Paris:

His most frequent relations were with the purveyors of food and drink, whose agents plied their trade vigorously through the streets and lanes of the Latin quarter and worked off their poorer goods on scholars and their servants. There were the hawkers of wine, crying their samples of different qualities from the taverns; the fruit-sellers, deceiving clerks with lettuce and cress, cherries, pears, and green apples; and at night the vendors of light pastry, with their carefully covered baskets of wafers, waffles, and rissoles—a frequent stake at the games of dice among students, who had a custom of hanging from their windows the baskets gained by lucky throws of the six. The pâtissiers had also more substantial wares suited to the clerical taste, tarts filled with eggs and cheese and well-peppered pies of pork, chicken, and eels. To the rôtissiers scholars’ servants resorted, not only for the pigeons, geese, and other fowl roasted on their spits, but also for uncooked beef, pork, and mutton, seasoned with garlic and other strong sauces. Such fare, however, was not for the poorer students, whose slender purses limited them to tripe and various kinds of sausage, over which a quarrel might easily arise and “the butchers be themselves butchered by angry scholars.”

'Clerks' here means students. You'll notice that a lot of the foods mentioned are pre-cooked, but the fact that their servants are also buying uncooked meat implies that at least some of them had cooking facilities. That might start you off on student food, but hopefully someone who knows more about the period will come along.

Edit: Ah, cool, thank you so much for the awards!