Transmission slip is not normal for a car with only this many miles. Low trans fluid can cause this problem.
The dealer might say a flush is normal regular maintenance. Check your owners manual to see when changing your transmission fluid is recommended (mileage/months). You might have to pay for this as changing fluid is normal to prolong the life of the tranny.
If the transmission still slips after the flush and the car is under warranty. Have the dealer fix it under warranty. Slipping is not good. It will only cause the transmission clutches to wear out faster. This would then require the trans to be pulled out and repaired.
One thing to keep in mind when doing warranty repairs. The dealer only gets reinbursed by the manufacture for the wholesale cost of the parts (the dealers cost of their parts). Plus only a portion of labor required to do the job. If the customer pays for the repairs, the dealer will charge full retail price for parts plus all labor cost required to do the job.
I am not saying the dealer will do you wrong, but you can see there is an incentive not to do warranty work.