I think my mom is trying to guilt me into pleading the fifth
Are you giving your mom the silent treatment?
Oh dear, now I'm realizing this is not a good time to tell her about my sexuality
It's your choice to come out of the closet or not. Don't let your mother force you to do or say things that you are not ready to talk about. It's okay to be patient and wait until the time is right.
I just want to get this over with. Maybe I will find my own answers.
Your choice, your time. Drop the bomb when she is relaxed and happy to counteract the upcoming shock of the news.