AIO my boyfriend's family made no effort to meet me

My boyfriend(m29) and myself (f42) have been dating two months now. I've met his daughter (5) and he's met my kids (f9 and m16). He's brought his daughter for sleepovers and we got to spend a weekend all together at a hotel last weekend. This weekend was his birthday weekend and he wanted to spend it camping, but had to pick up his daughter from his mom's house where he lives. His mom looks after his daughter every weekend because he works out of town twenty days of the month, and one of his sisters helps as well, so I kind of hoped/assumed they would want to meet me since I'm in her sons life as well as his daughter's. When we pulled into their driveway to pick up his daughter to bring her on the camping trip. His mom and sister were just getting out of the car as well (they'd brought his daughter to the store in town for camping supplies) and his mom and sister neither looked at me nor approached the car to introduce themselves or give me a chance to do so. Like they literally had zero acknowledgement of me being there despite being his girlfriend, and obviously it's serious between us since I've been able to meet his daughter and he's met my kids, so I did feel a little put off by them making zero effort to greet me or anything. My boyfriend went inside with them to grab his camping gear, asking me to stay in the car, which kind of furthered my insecurity. I waited for about fifteen minutes before just him and his daughter came out. On the way to the camp, I asked him why they didn't talk to me and he kind of shrugged it off, telling me not to worry about it and that his sister was just "bitchy as usual" and his mom wasn't ready to meet me yet and I needed to give her time.

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The thing is, I really love him and I want this to work. I could see myself marrying him one day, he really is a great guy and hard worker and good with my kids. But I'm worried his family is going to be an obstacle, especially going forward. He told me its because of our age difference and how fast we're moving, but I don't really think that matters when we are both consenting adults who can make our own choices and what's best for our children and ourselves. Anyway, AIO for being annoyed and a little concerned that his family made zero attempt to talk to me or welcome me?