It could happen. Going slow and gradually increasing the size of things you use can lessen the chances of this and allow you to decide whether or not to stop, remain at that size or move on to something larger.
If you decide to move forward with this fetish you need to make sure you use ONLY products made specifically for this purpose. No household objects. If you use anything other than a sex toy you could cut, scratch or otherwise harm yourself. And always use plenty of lubricant.

Remember to do kegal exercises. That will tone the muscles somewhat.