Is 9 years too big of an age gap for dating?

The normal "creepiness equation" is half your age plus seven, which in this case comes out to 21 (and a half) minimum for you. So hate to tell you, but according to the universal formula(tm) that's creepy, dude. Oddly enough, when you hit 32 this formula gives 23 years minimum which she'll be at the time; in other words, it's a "rule of thumb", take it with a grain of salt, but by usual definition that's definitely in the creepy territory.

Also, even if neither of you care about what other people think (Which is how it should be), your relative life stages will matter far more. At 20, she's probably still a student, and you're... something else? Consider that and the upcoming life changes for both of you and how you'll deal with them. This is also why it makes sense that 32 years and 23 is fine, while 29 and 20 looks creepy. But the upshot is that nothing in life is ever certain.

Also, if we'll take this "relationship advice" style, "everybody else is taken" is a TERRIBLE reason, regardless of the age. ;)

Maybe. My soon to be ex of 30 yrs is 10 yrs my senior. The problem I found through out the entire relationship was He expected me to act and behave his age. 10 yrs didn't seem so bad in the beginning but as time went by 10 years became a lifetime. It did matter. How on earth can some act 10 yrs older when you haven't lived those ten years?

No. Thats reasonable actually

No, not at all. I was 19 and my husband was 27 when we got married. That was 18 years ago!
It honestly depends on the two people involved and 9 years is not that big of an age gap.

I don't think so. It only really gets complicated if it's 20-30 years gap (or more).

It could possibly work.

Not at all.

It's ok...

yes

No

No. When I met the man I married, that was our age gap.