How do I bring up a one week trip with ldr gf to my mom?

I’m a 20 year old male. My household is kinda of in shambles since my parents consist of my step-dad, biological mom, and two younger sisters. I have a good relationship with my mother, and always have. However, I don’t have a good relationship with my step-dad. He’s very controlling and narcissistic. This is important because recently there has been a little bit of drama and conflict between my parents and my mom wants me to really focus on work so she doesn’t have to rely on my step-dad financially. To which I am currently working and helping around the house while waiting for summer sessions to start for college.

Going back to early December of 2024, my ldr gf and I have made the decision to see each other (for the first time actually). And plan on doing so for a whole week. She’s from the far ends of the East Coast while I’m from the opposite ends of the West Coast. Fast forwarding to now, my girlfriend has already paid for her ticket and hotel, and I’ve been financially preparing myself to help pay for things such as tickets, food, etc for the both of us.

The problem is that I don’t know how to tell my mom that I already reserved a week off at work a couple weeks ago to spend time with my girlfriend. It also doesn’t help that I won’t be at the house either because I plan on spending the night at the hotel with her for the week. She knows that I’m going to go to Disneyland with my partner, but I haven’t mentioned that I took the week off to be by her side the whole week she’s here because she told me some time after I reserved my week to “not call off on any days at work”. At this point I’ve been lying to her, and I don’t want to lie even more by telling her I’m doing something I’m not. And the problem is that I feel like my step-dad will play a bit of a role in making my mom feel like a bad mom for letting me do whatever I want apparently. Though I pay bills and have every right to have a life outside of home.

Sorry if this leaned a little towards a rant. It’s pretty late right now, and this has been causing me to lose a bit of sleep. Thanks for reading