The problem here is that there is no such thing as a "top" in the period, in the sense that we use it today - to mean a garment worn only on the upper part of the body, along with a skirt or bifurcated garment on the lower half.

As I described in a recent answer on Anglo-Saxon clothing, Anglo-Saxon women in the time period you're writing about typically wore one to three layers. The most common layer worn by all women was a gown with long sleeves made out of wool, fairly loose and unfitted to the body since it would have no fastenings and therefore had to be slipped over the head. It's most likely that this would have rectangular sleeves with little to no shaping set into the side seam of the gown, and that triangular gores were inserted into the side seams as well in order to make the lower half full enough to allow walking, sitting, etc. Most women would also have worn a linen smock, cut on roughly the same lines, underneath this gown in order to protect their skin from the wool and protect their wool from the oils and sweat of their skin.

As for the third layer, let me copy and paste from the earlier answer:

Women wore what's known as a "peplos dress" similar to the ancient Greek peplos: a tube of fabric that encased the body and fastened over or at the shoulders with relatively similar (if not actually twinned) brooches or pins, and clasped around the waist or hips with a belt. While the belts do not survive, there is evidence of them through metal fittings remaining at the waist of the skeletons recovered through archaeology, and metal items around the thigh area that were evidently hung on a belt. This outfit was common to Germanic and Scandinavian women in Europe

The question you need to ask is whether it was acceptable for women to take off their gowns and be seen in just their linen undergarment, or to take off everything and be fully naked. This is a difficult question to answer, because your story is set in the Migration Period, fairly early in the history of Anglo-Saxon England, and prior to the conversion to Christianity. However, we do have some evidence that nudity was seen as shameful for women earlier in the Iron Age among Germanic tribes - if we take Tacitus' Germania at face value, women who committed adultery were stripped naked by their husbands and had their hair cut off, for instance. (We have a number of pieces of evidence that male nudity was somewhat normalized.) I would not recommend having the character strip fully naked in the story.