I don't know what to do

Abbey

So I'm in 9th grade and just started dating a 11th grader from a different school however he was friends with a friend I have and that's how we met and the friend we met through has gotten really jealous that we started dating and idk what to do I'm kinda scared

Also how to I tell my mom I have a boyfriend like she won't care that I'm dating an 11th grader but how do I tell I'm dating someone