Is It Okay to Mix Past Tense With Present Tense in Story Writing?

rjssim wrote:

We're just standing outside the Blue Velvet right now. We're gonna go in there and have a good time tonight!

"I hope the drinks are cheap!" I said. "I don't got a lot of money to spend."

"Don't worry bro, I got you covered for drinks," Paul replied.

Ashley swings her purse. "Come on, let's go in!"

To me that looks like reported speech more than past tense, like you're alternating between telling the story from first person perspective to third person.