Mom & Relationship Issues

A month ago I got into a new relationship, but my mom doesn't allow me to go on dates with anyone until I turn 16. I tried to date someone in the past and she put so much pressure on the relationship that my ex broke up with me because he felt like he was getting in between me and my mom. Now when it comes to anything about relationships, I get so much anxiety about telling her anything because I'm afraid that she'll make me feel so bad for dating someone before I'm supposed to and put pressure on the relationship. I made the mistake of telling her I'm in a relationship with someone and now we can't hang out outside of school at all. I felt like she'd be more lenient since I turn 16 in 3 months, but I was wrong. I cried for hours because I felt like this relationship was going to fail like the last one and it was going to be all my fault. My girlfriend reassured me and said she didn't mind waiting, but she recently asked if I could come over for an event at her house but I'm too scared to even ask because I don't want to make the situation worse and make my mom upset. My mom has never seen my girlfriend and doesn't know what she looks like, and I don't mention her out of fear that she'll be upset with me. I was thinking I could just say she's a friend when I ask, since I've only mentioned her once, but my girlfriend's mom knows we're dating and I'm scared she'll say something to my mom about our relationship. I'm posting this here to just let my feelings out about the situation, but if anyone has any advice, it'd be greatly appreciated.