Oh no... what to do??

Last night I posted a question about my new kitten having fleas. We used a flea shampoo and an over the counter flea med on her. Today I saw many responses as to NOT use a flea shampoo and med on a kitten... it could be hazardous and deadly ! I'm worried now; what do I do?! We arent sure of her age maybe 8 or 10 weeks. We do have a vet appointment tomorrow morning for vaccines and check-up.