Profecto Latine rogare licet!
Let there be no doubt:
Questions and answers in Latin are permitted, welcome, and encouraged!
You need no special reason to express your question in Latin: you could ask in Latin because it's fun, because you've never tried it before, for the novelty, for practice, because of the sheer pleasure of expressing yourself in Latin, because everything sounds better in Latin, to make a witty reference to Erasmus, or for no reason at all.
Another answer mentions studying Latin for four years and still being unable to write it or speak it. I've talked with a number of people with similar experiences. I suggest that if you spent four years studying the language and still can't communicate in it, the problem is that you didn't practice communicating in it.
There is a movement in Latin pedagogy now that proposes to teach Latin the same way you'd teach any other foreign language: by using it. We already have a tag, llpsi, for this movement's flagship textbook, Lingua Latina Per Se Illustrata. Latin is special because of its very long written tradition, in which a small set of classical writings were used to teach the language (including speaking it), so you spend a lot of time with those. But you only come to really know a language by using it. That's how you get a feeling for its turns of phrase and habits of thought, the way its prose differs from its poetry, its connotations and cultural reference points. You've got to use it to communicate with another person, where it matters to you that you and the other party get the information right.
Not everyone agrees with this approach, of course, and we don't all need to agree. We should just make clear that if you want to post in Latin, you should do so without hesitation! Some of us want to see and answer those questions. If you don't feel like you have enough mastery of Latin to ask without making mistakes, ask anyway! You may receive helpful corrections from others more knowledgeable. Discite faciendo, scribendo, legendo, te exprimendo!
Of course, you will know that by writing in Latin, the more non-expert users might not be able to understand your question.* I trust that you can use common sense in deciding whether to supply an English translation, or maybe a little English crib, as I did in this question.
*Or you might unwittingly help the non-expert users by asking something they wanted to ask, struggling with the same difficulties they're struggling with, and giving them just the bit of help they needed. If anyone fears that questions in Latin might put off beginners, consider that despite being a tiro, I had no difficulty composing this question.