Dating an older guy

I'm 20 and my boyfriend is 33 we work together and have been dating for almost 4 months. I've even met his daughter and we get along great but I haven't met the rest of his family. He's met my family and although they didn't like the idea of us dating they've come to really like him. I just can't tell if he wants me to meet his parents and sisters or not. I've tried to talk to him about meeting them and he tells me he's going to introduce me but that his sisters can be very judgmental and always blows off opportunities for me to meet them and I can't help but think that he really doesn't want me to meet the rest of his family. I know that people may think I'm trying to use him or that he just wants someone young but it's not like that at all for us. Has anyone been in a similar situation or have any advice on how to handle this situation?