is this strange

Im noy crazy and 100% trust my boyfriend but he told me a girl from his work was going to tour his college. I said oh thats good. Well he couldnt do it the day she wanted to. He told her last minute and i was like well arent her parents going and he goes no shes not even doing a really tour of the school. I just find it strange because i caught her once over texting asking him why he nevers hangs out with or takes her to lunch and my bf just was like well shes my gf so thats why. Obviously i dont trust her but the whole thing is weird. Why would she go tour that 2.5 hours away without her family or making it a serious thing. I feel like shes just doing it as a hangout with him. What do you think? I trust my bf and he doesnt se this but as a girl if it wasnt my bf its a snart move lol