Unfortunately you can’t do much for now. Just keep doing what you are doing and pray a lot. In a few years you will be free to convert. It is great that your boyfriend is Catholic. Fellowship with other believers is so important. This forum can offer something similar so just feel free to ask questions or ask for prayers. Your mother is probably freaking out because as far as she is concerned you are leaving true Christianity for the whore of Babylon or something

Be gentle with her. Learn as much as you can about the Catholic faith and teach her about what we really believe and what our history is.
God bless.