You need to put more distance in between you & your mom. Like a few states, minimum. Ideally like a whole country and a couple oceans. Don't go anywhere obvious, like to a family or friends house. If you're going to get a hotel room, pay cash and don't give them a real name. Don't leave a paper trail.

Get rid of your cell phone, especially if it's on your mom's plan. Remove SIM, turn off location tracking, and then get rid of that phone. Leave it somewhere far away from where you're staying. Go to the nearest CVS / Walmart / Walgreens and buy a prepaid burner phone with cash, you can get Net10 really cheap. Don't use any credit or debit cards if your mom has access to the account. If you need to pull cash, use an ATM close to your hometown, get enough that you won't have to do it again for a while, and then book it far away from there, again being careful not to use anything close to where you're staying so you don't lead them to you.

Check what your grandma has that can be tracked. Make sure she follows the same steps. Get an Uber from your burner phone and once you get to the destination, ask them if you can pay them cash to take you somewhere else without using the app. Ask the driver for their number and ask if you can call them directly next time and pay cash. Explain why. In my experience most Uber drivers will jump at the opportunity to drive you wherever you need to go and will happily accept cash. Don't forget to tip them.

So now you should have a place to stay that's not in your name, a burner phone that nobody knows about, a pocket full of cash, and a driver that's off the books and can't be traced. Time to disappear. Good luck with everything & be safe!