If it helps I'm currently in the situation that your friend is in but I'm a couple months into the relationship, it is hard as all hell to learn about a fringe lifestyle/sexuality, talk to family and friends, deal with issues of jealousy, masculinity, pride, timekeeping, worry about protecting feelings of my partner with overburdening her or pushing her away and worrying greatly about what a long term relationship looks like or what I'm meant to do with myself when i know she's nesting with her other partner and I'm freaking out.

Despite all that we've fallen madly in love and I've not been this happy before, maybe it'll still go wrong and I'm a man confused and lost at sea quite often but if the person you like feels the same way i encourage them to try, communicate a lot to each other in positive ways and they'll be alright, but do be conscious that they will be hurt a little sometimes and that's ok, if you want them you have to be ready to look after them when you hurt them, make sacrifuces for each other just like in a normal relationship and care for each others needs.

Don't put too much expectation on this, you have 0 clue if they'll even say yes.