The most reliable information we have about Blackbeard's early life comes from one short paragraph in the contemporary book A General History of the Robberies and Murders of the Most Notorious Pyrates published in 1724 by Charles Johnson (possibly a pseudonym for Daniel Defoe):

Edward Teach was a Bristol Man born, but had sailed some Time out of Jamaica, in Privateers, in the late French War; yet tho' he had often distinguished himself for his uncommon Boldness and personal Courage, he was never raised to any Command, till he went a Pyrating, which I think was at the latter End of the Year 1716, when Captain Benjamin Hornigold put him into a Sloop that he had made Prize of, and with whom he continued in Consortship till a little while before Hornigold surrendered.

Like many of those who turned pirate in the late 1710s, Edward Teach (also spelled "Thatch" and a variety of other ways in contemporary documents) had served as a privateer in the Spanish War of Succession which began in 1702 and the American theater of that war called Queen Anne's War (this is what is meant by the "French War") and when that war ended in 1713 he found himself out of (lawful) work. Although the first mention of Blackbeard as a pirate is at the end of 1716 when he was given command of a captured ship, he seems to have originally been a member of Benjamin Hornigold's crew as a privateer and Hornigold began engaging in piracy by at least the beginning of 1714 (Little, p. 143-44).

We don't know how old Blackbeard was though some have speculated he was born in about 1680, but this is based entirely on looking at the woodcuts made of him after his death by people who never saw him as well as the assumption he would have had to be a little older than the rest of his crew who would have averaged in their mid to late twenties in order to command respect. However, the pirate captains Charles Harris and Walter Kennedy were only 25 and 26 when their careers ended so in truth Blackbeard could have been born anywhere from around 1680 to 1690 and we really have no way of knowing (Little, p. 144). He is reported in A General History to have married a young planter's daughter in Bath Town, North Carolina, but this doesn't necessarily say much about his age either.

As for his name which is standardized as Edward Teach, we really don't even know if that was his real name as some pirates would have adopted aliases to protect their relatives (and avoid recognition by relatives). The most reliable source for where he was born is A General History since the writer of that would have had access to contemporary records and that says he was born in Bristol in England, but some modern historians and authors have claimed he could have been born in Jamaica, Virginia or North Carolina (Little, p. 144).

And that's really it. Those are the only "hard facts" we have about Blackbeard's early life. We can look at his later conduct as a pirate to perhaps make inferences about what he was like before he enters the record, but that's all. We know in his last battle with the pirate hunter Lieutenant Robert Maynard in November 1718 he showed a lot of boldness and daring when he boarded Maynard's vessel even after his crew had taken heavy losses, and then fought on by himself even after he was outnumbered and surrounded, eventually dying with at least five bullet wounds and dozens of sword cuts. In short, he was a hardass and this might have been the same "uncommon boldness and courage" with which he apparently distinguished himself in Queen Anne's War. We also know he seems to have treated most of his prisoners fairly well by the standards of pirates, though it's implied he may have abused his teenage wife (Little, p. 145) and he is also reported to have apparently randomly shot one of his own crew through the kneecap one night and maimed him for life, only saying damn him and that "if he did not now and then kill one of them, they would forget who he was" (Johnson/Defoe, p. 84).

Sources:

How History’s Great Pirates Pillaged, Plundered, and Got Away With It: the stories, techniques, and tactics of the most feared sea rovers from 1500-1800 by Bennerson Little

A General History of the Robberies and Murders of the Most Notorious Pyrates by Charles Johnson/Daniel Defoe