Check out the (new diver q&a topics) from July. Another new diver, Rochelle, had issues taking her mask off and much of the advice we gave to her would be helpful for you. (there’s too much for me to try to copy it).
I am a major nose breather and always will be. Sometimes I STILL get water in my nose - after hundreds and hundreds of dives - and I’ve just learned to go with it. Most of the time, I pretend I have a stuffy nose and it really helps me focus on being a mouth breather. Work on mouth breathing when you’re doing chores around the house so you can get really good at it.
The more time you can spend under water without your mask on, the more normal it will seem. If you have a bathtub at home, take your snorkel with you and lay face down.
So check the forum for the tips we gave Rochelle and most importantly, be patient with yourself. Lots of us have been there and you’ll get through it too.
Good Luck!