Boy advice

Help I'm young and not allowed to have a bf but I have one and every text I ever sent him gose to his phone and his moms we have been together 10 months but she Hasent said anything to anyone but her best friend who's like a older sister to me He dosent know his mom reads them but I swear I wouldn't tell to my"sister" but he always writes stuff like I love u and stuff I won't say