Does she still like me deep down

I recently met a girl through a mutual friend and we somewhat developed feelings for one another. It wasn't until a friend of hers asked me in a social setting if I would go on a date with her, that I realised she really "loved" me.

I felt very uncomfortable at the time and I didn't want to say no and break her heart. She is 3 years older than me, and I've never been in a relationship before. I told her in private a few days later, that I liked her but I would disappoint her as a boyfriend - I regret friendzoning her. Ever since this moment, she has always been pointing out my flaws and telling me how I could improve. She wants to see me in better clothes and is giving me all sorts of advice for getting a girl. She also keeps giving me my plus points. But something is telling me that she really really wants me, I mean why else is this girl still talking to me.

I wouldn't mind going on a few dates with this girl and see where it ends. What should I do?

Ask her out.

Yeah but I already told her that I would disappoint her as a boyfriend.

In any case, we have planned to go out soon. I'm just so shocked as to how I even met a girl and became close with them. It's the first time in my life, I've met someone who I feel very comfortable around

Ask her if she wants a rusty trombone.