Hi Alejandro
Totally loving the style of the girl on the bike. If you don’t mind me saying, the only thing that bugs me, is the eyes in conjunction with the facial expression. When I say the eyes, I mean how they are staring. I think you could put more character into the model.
Might be worth studying some of Carlos Ortega Elizalde’s work (www.artstation.com/artist/carlosortega) to take this model into the fantastic realm 
Just an idea, have you thought about putting some comedy into this piece?? I’m thinking, maybe the hair issues one may have with taking off a bike helmet. That in conjunction with a reactive facial expression might give some life/story into the piece. Anyway just a thought
Keep it coming! 