The only viola I can get ahold of now is a size 17, would it be a bad idea for me to try and learn on this?
I`m 5`5.

Do you have a teacher? Ask her.

Are you switching from a violin?

What do you mean "all you can get a hold of? There are lots of violas out there. Can you explain?

You can always play it like a cello. (It`s called a vertical viola. No, I am not kidding.).

Or you can play it South Indian style, between your foot and your chest (now I am being a bit flippant).

Or you can strum it like a guitar. or put frets on it and call it a viole and play it on your leg (now I am being flippant).

So, go for it. But 1st, tell us why you can`t get a different size.

I don`t have the money to buy one, this one is my father`s.
I play the violin, and have a violin teacher, but she doesn`t play the viola.
I am just wondering if I would be able to play one this big for awhile and then switch to a smaller one later, without it messing me up. I know I couldn`t go from a full size violin to a half size one and still be able to find the notes.
I can`t reach the scroll on this one, and I can`t hold it up for very long, but I figure any viola is going to be heavier than a violin, so I`ll have to get used to it.

As far as getting "messed up" from changing sizes: The more scale lengths you play, the better skill you will have at intonation. Sure, you will "mess up" at first, but the process will improve your skills rather markedly.

Every child that starts on fractional goes through this at switch-over. And those who play more than one instrument go through it more frequently.

I would not worry about that part of it.

What I would worry about is the size and awkwardness. Take it easy at first and show your violin teacher your set-up and position with the viola. You can get injured if you push too hard (get fatigued) in an awkward position. But if you build up to it, you may be just fine.

Since you have a violin teacher, you have a ready resource for this.

Sounds to me like a sure recipe for an injured shoulder.

Liz

Alrighty, I`ll give a try. I`ll start out slow and knock it off if it interferes with my violining.
Liz, do you mean even just with like, fifteen minutes a day? I mean, the violin really hurt my shoulder at first, so shouldn`t I expect some pain with the viola, too?

Keep in close contact with your teacher---and show him/her. Far better advice will come forth than you will get here on the internet...