Nice guy, lying to best friend

So there’s this really nice guy I met while I was working. He found me on Facebook and we started chatting. We have really nice long talks about life and he’s a genuine guy.

He wants to go on a date but it’s kinda wierd because I’m 23 and he’s 29. That’s the biggest age gap ever. I also haven’t told my best friend who is my roommate about him because she thinks it’s unprofessional that I met him at work.

What should I do? I haven’t met a decent man in so long!

Edit: also we’ve been texting and snapping non stop and I haven’t told my best friend about him at all. I feel really guilty because I like this guy but I feel like she won’t like him because he’s older and we met while I was working at a wedding and he was the best man