Hi Hello991, First congratulations on your new relationship. Masturbation is not something to be ashamed about. It is I believe something most people try or do. Unfortunately, some religions describe it as a sin . Giving the act a "dirty" feel or name. I don't think you need to tell your new girlfriend about your past habits. You have nothing to feel bad about. You are not horrible. Give yourself some self compassion and just enjoy your new relationship! Focus your feelings on her and yourself. Good luck,much happiness, and peace!