I'm a 19 year old female just recently graduated with no record at all. I snapped a picture of my grannys debit card and uses it to pay my phone bill a couple times then from that it went on to buying clothes and shoes. At that time I had spent well over I accidentally deleted the picture of the card out my phone so I went back and took the picture again not realizing that this was a different card and the first one had been cut up and they replaced all the money. But about time I found that out I had spent a little over 2,000 dollars on the other card. They're not pressing charges but someone said it's a good possibility that the bank might press them. Just because of the fact that they replaced the money the first time so I'm guessing they want they're money. And I do have a job to pay them back plus interest. I just really don't want to go to jail.
What do you think my punishment will be?

& also earlier this they said that someone called and said that I was on house arrest but how when I never went to court nor did they send me a ankle braclet?

Yes it is most likely that the bank will press charges, and you will of course be forced to repay everything you stole. I am surprised the grandmother is not being forced to press charges by the bank or be liable to pay all the money her self.

I don't think she is but I know that she said she think they will.
They told her for now put me on house arrest until they collect all the information. But does that mean afterwards it's a possibility I could face jail time?
Or will they cut me some slack and just let me pay it back being that its my first offense ever.

The problem here is that this was not an isolated incident. You systematically stole over $2K over an extended period. So yes the bank will probably prosecute.

As to the house arrest thing, someone is pulling your leg. House arrest is issued by a court in addition to bail rather than putting you in jail.

If your record is otherwise clean, and you agree to restitution, you may avoid jail time.