The main thing is most people won't care, nor will they actually want to know. I don't mean that disrespectfully, but a lot of people I've known to come out did it for attention, and it really angered me as anything we ever did, such as bench them for the night, or ask them to be quiet, was because they were Gay / Lesbian / Bi / Transgender.
As long as you don't turn this into Pity the G/L/B/T, then you'll be fine to come I (I can only guess), and if you're uncomfortable pretending, then even more reason to do it.