'I would be so grateful if...' rude?

I am a high school student and I often use ‘I would be so grateful if you could take a moment to…’ or ‘I would be so grateful if you could help me.’ or something like that when I am writing an email to teachers.

My QUESTION IS..
IS IT RUDE? I really don’t want to be rude and I have been always trying to be nice and be polite to my teachers. But I don’t know if my ‘I would be so grateful if you could..’ emails are rude/un polite. Could you guys help me? Thanks .