Wetting the bed can happen to anyone at any age. And since it was just a little bit I wouldn't worry too much unless it continues to happen.
If the bed wetting stops and only happened last night and doesn't happen anymore then it's probably nothing to worry about.
But if it continues to happen I would tell your doctor about the bed wetting so they can do some tests to make sure nothing serious is going on with your bladder or kidneys.
You doctor can also prescribe you some medicine to help slow urine production in the night and prevent bed wetting.