How long for a male dragonscale betta to grow out?

A pic of him/her would be helpful. Sometimes some betta are hard to sex especially plakat males to females.

Very easy to tell males and females apart. Females have an egg looking thing sticking out if their bottom near the anal fin, their bodies are also shaped differently with a much smaller head compared to males. If you bought your fish from Petsmart, their dragonscales are almost all of the plakat or short fin varient. If that's the case then its fins will not be growing any longer than they already are.