Heeelllppppp??!! i got asked out...idk wat to do?

okk so i just turned 12 and my moms friend and her son came over here 2 our house 2day (without me knowing.) i didnnt know him at all and he suddenly came into my room on like, my worst hair day ever and asked me out. i say "idk" becuz i dont really know him. lol he gave me his # and told me to text him. i've never gone out with a guy b4. i've been asked out and stuff but only a couple times and the guys were all not my type at all. helpp.? >.<