Turtle shell help!!

[TURTLEDUDE]

I have been caring for my 5 year old nephews pet turtle SHELBY for the past 2 years. She is about 4 years old. Her aquarium is 55 gallons with a good filter. Her diet is meal worms, shrimp, and often feeder fish. Her basking light is about 65 WATT and she seems happy BUT I'm am worried that she may have shell rott but I cannot tell. If anyone out there can take a look at these photos I have taken of her and give me your personal opinion on wether I should worry or not. Are there any home remedies if she does indeed have shell rot? Please help.