LST on autos?

I've trained one of my autos to the point the main stem is basically horizontal. Shes got a fair few tops on her but I've never grew autos so I dont know wether to do the same with my other one? They are both on day 23 from seed but the trained one(American pie) seems a lot bigger and has started flowering whilst the other is short and bushy(zkittlez OG) and still yet to show sign of sex. How long do autos usually take to go into flower? My other one shown it was a female around 2 weeks old