You can actually keep your distance from them indefinitely - just jog away from them while they're following you, and when their attack animation begins, sprint away for a couple of seconds. The easiest way to actually kill them in the beginning is probably to just kite and shoot, which might take a while but it will get the job done. I wouldn't bother meleeing them without a bronze buckler and a decent grasp of the parrying mechanic. They aren't supposed to be very common so perhaps you've just been unlucky so far.

Other than that, once you have enough copper and tin, make yourself a bronze axe as a first priority, then chop down some birches and oaks to get fine wood. You can use that to make the second tier bow, which is worlds better than the first tier one and will let you deal with trolls much more easily.