Around that age I was in a similar situation with a girl who was 5-6 years older than me (and was also above me in my company) who was very actively interested, and she looked young for her age, she got a fair bit of attention from other guys too because she was pretty extroverted and admittedly had a kickin butt.
I wasn't really comfortable with the idea though because the concept of getting involved with an assertive older women seemed suspect to me, like there was going to be Freudian stuff going on there and it was going to turn it into some kind of weird codependent mother/big sister deal that wouldn't really be healthy for anyone involved in the long run.
I wasn't sure if I was just being cynical though.
Thankfully your story has confirmed to me that I was almost definitely correct as to how it would've turned out, and probably made the wise choice.
There isn't anything wrong with being with older women casually, it's just that if the younger guy is a little insecure or doesn't know what he's doing she'll absolutely turn him into a lapdog and he's probably never going to develop into an independent man.