How can I tell my mom I do not want her coming on vacation with us?

Not technically mom related but I’m awful with confrontation and we planned to go on vacation in July just me, my fiancé, and our 2 kids so we booked a suite with 2 queen beds, a living room, and kitchenette. After the fact we booked it a month later my mom says “I want to go” and then started planning how all of her bags would fit in our car and earlier she texted me “I’m putting vacation days in today” I said I didn’t know you were going and she said “I can just stay home if you don’t want me going” then of course I felt bad and don’t want to say no. I’m just not sure how to tell her without her getting upset. We just had no plan on anyone else coming with us since it was just a family vacation. How do I tell her without being so blunt about her not going? Even if she goes I wouldn’t mind but would rather her get her own hotel but I feel like that might even come off as rude I just hate when it comes to confrontation.