How do I get over "dating up?"

"Dating up," "outkicking my coverage," whatever you want to call it; never really experienced it. Both lookswise and statuswise my past partners and dates have all been around what I feel to be closer to me (a solid 6?).

That is until now. I have a 2nd date this weekend with a girl who I would never imagine myself with in a million years. Absolutely gorgeous and most importantly, a personality that is exactly what I'm looking for in a partner but rarely get to date.

We had a great time our first date (drinks/light food) and while I was clear in my interest in a 2nd, I didn't really expect her to accept.

So now we have plans to visit the zoo and I have all kinds of dumb thoughts running through my head.

Looking for people who have had experience with this thing, or just wanna call me an overthinking dummy. I know the basis is a lack of confidence but it's never really presented itself like this.

Thanks.