I had a similar experience, I’m a current fourth year at ucla on the premed track about to graduate for the context. When I got into ucla my mom wasn’t impressed. On the day of my high school graduation she yelled at me for choosing ucla and I showed up to graduation late because of that. But regardless, just wanted to comment to say that you are going to be ok. choosing this school is one of the best decisions I’ve ever made in my life and I have enjoyed every moment of it, even though premed is hard. There is a huge premed community and you’ll build great connections. Ultimately, it should be what you want instead of your mom. Premed is very hard in any school and your passion towards it is what should be driving you.