"Tangerine" includes quite a wide spectrum of varieties, with varying cold-hardiness. But it's safe to say that none of them would survive zone 6. If it were one of the Satsuma types, it might take down into the mid-teens if fully hardened. 'Dancy' types might to into the lower 20s F. Hybrid mandarin types would more likely be mid- to upper 20s in hardiness. Any of these might survive somewhat lower temperatures with serious wood damage, but none would likely make it through single-digit (F) temperatures.

Just keep it in a pot. It is from seed so it is not going to be identical to the original tree.

Actually nearly all of the mandarin types do come true-to-type from seed, from nucellar (clonal) embryos. Clementine and King are the only exceptions I can think of (and Temple, if we include known hybrids)

So at what temp do I need to start bringing it in? Thanks alot everyone for your help.

For a potted tree, I'd avoid frost. Certainly lower than upper 20s F would make me nervous.