I think if you want to accompany your singing Mrrzy you probably want to learn some simple chords to go along with what you're singing. A guitar, autoharp, dulcimer, and piano are very useful for that. The piano is the least portable of all of these. Guitar, autoharp and dulcimer take more tuning time. Piano is easy to play because if you press a note down you get a reasonable sound so you just have to figure out what notes you want from it, its also seems, to me at least, to be a lot more visual than guitar, a C note is always a C note.

I think trying out some instruments to find out what you like best is still a better idea than trying to follow a lot of the different advice here. Everybody learns in different ways and different instruments suit different learning and thinking styles better. You know your style best.

You needn't think that this will be the only instrument you ever learn either. Its easier to pick up a different instrument after you've achieved some competency on your first one.