Grinding is best because your only going to be as good as what you're going over. That said, If it's not peeling or flaking it can be sanded, pressure washed, and gone over if need be.
Grinding, epoxy primer with urethane topcoat is the way to go. We have had these thin mil systems in heavy manufacturing plants last more than 20 years.
After 13 years there is a good chance the sealer. As solar Columbia said, see how it absorbs water. If you can't grinder the floor yiu may have to strip any existing sealer off before acid etching. What is your goal with the floor?
Look up a process called "spray deck" we do alot around pool decks, driveways and walk way. Its design can vary and our company has had it down in commercial situations for over 20 years with no issues other then sealing when needed
If it is a true mma I'd go that route. They are very uv stable. Polyaspartic would also work. There are also brands of solvent based acrylic sealers that can be tinted, while not very chemical resistant they are cheap and easy to apply