Moving into new flat halfway through first year: help!

So there were some problems with my contract length at one accommodation (catered halls which, to be fair, were SUPER quiet and I didn't like them anyway), and I'm being switched to a self catered flat next week. I'm honestly just really afraid that I'd be completely left out in the flat since everyone knew each other since Fresher's and I'm the new kid, technically.

I'm quite social, I'm planning to leave my door open and go into the kitchen a lot, I've got interesting posters, am international but I had a complete British education so I socialize more with home students anyway etc etc, but I'm just worried about the 'intruder' factor. Like no matter what I do they'd exclude me since I'm the outsider and they'd think it odd if I butt in on their stuff. I'm honestly kind of terrified of that because I'm quite talkative and like going out so it would really be a bummer if my flat excludes me. A friend of mine in the flat opposite talked to them and they said they're super excited and are cleaning the kitchen for my viewing so maybe I'm being irrationally nervous, but I still am!

Have any of you been in this situation (as the new flatmate OR as someone in a flat accepting another flatmate late) and do you have any tips on how I could make myself at home in the flat and go along with them? Help!