i've seen archers as low as 80 in labby 1, but it all depends on your gear, normally i start there around 87-90 for melee guys, for archers, its all about fly and your safety spots. so in reality you can go at any level after you get fly and enough VP. you should definitely not go if they can 1 hit you, at least be able to take a few hits in case you cannot land in a safety spot.