Age difference does it really matter?

Hey ladies xx So I met a guy on badoo (dating website) we have a three year age gap. I'm turning 18 and he just turned 21. anyway we started to talk, ended up going on a date last weekend, the good old classic cinema date. Anyway we get Along so well, text a lot etc! We are going on a another date this Friday & hanging out Saturday! He seems keen on dating. I know that they're is age difference and that our life's are at different stages. But does it really matter?  My mum approves, thinks he is a mature guy with respect for women. Know has anyone's daughters been through this, or perhaps yourself? No harsh comments please.