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

Hi guys. I use TS4 for my sims story and I'm jut wondering is it okay to mix past tense with present tense? Like for example:

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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!"

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Is okay to use both tenses like this?