Can I be mad at my girlfriend over an ipad?
What happened to make you mad?
She won't let me use her ipad
You should not be mad about her not wanting to share her personal things. You can buy your own tablet to use if you want one so badly.
She should not be selfish and share her stuff.
While it may upset you that she won't let you use her ipad, you can't expect her to give you her possessions that she owns. It's also not worth it to risk your relationship over something as small as an ipad.