Dating ( Am I Trippin?)

So I'm an 18 year old graduating senior (female) , I recently met a freshman in college and we've been talking for 2 weeks. If I'm not mistaken he's 20 years old. He's asked me to go on a date. My point is as an 18 yr old what would the typical age range for myself be? My brother who's 24 is making a big deal of it, and same with my parents. I'm mature, responsible, I have freaking morals. Definitely not childish I just don't see the big deal. Not sure if it matters but of course I still live with my parents.