I'm scared to get into a relationship?

I'm a 21 year old male and by this age i'm getting pretty desperate for a relationship however every time the opportunity arises and things start to get a little serious with a girl, I get scared and back off. I used to think that the girls just weren't good enough which is why I back off but i realised that I'm just making excuses.

I have no problem talking/flirting with girls when it's no strings attached but as soon as a girl mentions a proper date or something like that i just get scared. I hate the whole idea of meeting the parents and all that, it's just a lot of pressure.

Any advice or motivation would be appreciated, 

Thanks.