He NEVER replies to my messages on Facebook?

Maybe he is still looking around and not for anything serious especially if he isn't answering your messages or he might play for the other team if he is noticing your hair or style. If you are sending him flirty messages and he isn't replying back maybe he is just too bashful to tell you what side hes on. Or maybe you are just acting Too Available maybe too clingy ?? Loosen up and just hang out with the guy and make simple conversation, let him come to you I know it sounds old fashion but it really works in most cases. It is rare but not uncommon that guys like the girls who take control, but majority of the guys love to chase the gals <3 And it has nothing to do with your age I was 21 when I met my husband who is 26 and we have been married for 7 years now so age is really like they say "just a number" but don't fall so hard for the guy and just go with the flow if something happens,but my best wishes to you <3 Just enjoy life and take it a day at a time.