Need some advice about this guy I met last night...

Well a friend of mine introduced me to a guy last night who I know likes me, this was the first time I met him and I thought he was nice and pretty cute too, we talked a little and quite got along and we both knew we liked each other and something could definitely happen that night.However this was when my friend took me aside and told me he was 4 years younger than me. Age is not important in this story but let's just say that I am legal and he is not so 4 years is quite a big difference and kind of made me take a step back.On my way home he was all I could think about and it left me very conflicted in if I should give it a try or not. He is too young for me and I have never been or wanted to be with someone that is (much) younger than me so I keep telling my self 'no'.However there is this part of me that really likes him and would love to meet up again and give it a go.Do you have any thought or advice on what I should do?