Peterhouse is a very open, friendly, and understanding college, and there is an active and welcoming LGBT+ community.
There is usually some sort of event every week, such as tea parties or film nights, and groups from Peterhouse go to university-wide events, so there is a wide variety of LGBT+ things happening that you can go to and meet people.
As well as running fun social things, the LGBT+ representative also available for welfare support for any and all issues, and able to answer any questions about LGBT+ things you might have (regardless of your gender identity or sexual orientation).
If you have any questions, worries, or just want to chat to someone before coming up, then shoot them an email at, LGBT@peterhousejcr.co.uk
Also, check out: http://www.lgbt.cusu.cam.ac.uk/ (not often updated, but worth a look to see what sort of things CUSU LGBT+ do)