Cats have a lower threshold for overstimulation than most people realize, and what looks like enjoyment can flip to irritation pretty quickly. Your tabby's biting is almost certainly a communication thing - she's telling you "okay, I'm done now" rather than actually being mean. Some cats just have shorter patience windows for touch, especially on certain body parts like the belly, tail base, or back legs. The biting isn't aggression; it's more like a "hey, stop" signal that escalates because you haven't picked up on the earlier hints (ears going back, tail twitching, skin rippling).
Pay attention to what happens right before the bite. Does her tail start swishing? Do her ears flatten? Is she nipping at your hand before the actual bite? Most cats give a bunch of warning signs if you watch for them. Try petting sessions in shorter bursts - maybe 30 seconds to a minute, then give her space. Focus on areas she seems to genuinely enjoy (usually the head and cheeks) and avoid the sensitive zones until you figure out her preferences. Some cats just don't like prolonged stroking of the body, and that's totally normal.
The fact that she comes back for more petting means she does enjoy interaction, just on her own terms. You're not doing anything wrong really, just learning her specific personality. Once you recognize those early warning signs and respect them by stopping before she bites, those sessions will be much nicer for both of you.