Bath tub has about 3 3-5 inch cracks in the fiberglass

I’ve lived in the home 6 years now and my niece has lived in the guest room upstairs and used the bathtub.

She left about a week ago and I went to clean and found these cracks. The tubs also feels creaky.

I was looking to reglaze but I’m afraid it could be water damage even though I don’t see anything downstairs in the ceiling or walls.

Any advice?