Advice 🤦🏽‍♀️

My and my boyfriend of 3 years are finally getting an apartment together and I am so excited 😊 But my mom is hesitant to let me go live with him.. i guess cause I'm the youngest and the only child left wih her. So last night she told me boyfriend before we move in together she wants him to talk to her and my stepdad( since my real dad passed away) but he has no idea what so say or how to act .. any advice or anything to help me help him. ?