Jeff is a gnome that pretended to be her first boyfriend and he is part of the gnomes that pretended to be her first bf. you should watch the first episode hes in that
I really don't think she'd choose either. To her credit, Mabel's not one to lie down and take such unprogressive choices.
She'd dramatically exclaim something to the effect of, "I would rather DIE than have my hand forced into date-lock!" before comedically attempting to kill herself, and then Dipper would hastily tell her not to be so drastic before helping her find a way out of it.