I am taking my first plane ride and was wondering what size suitcase to get only want carry on?

The International Air Transport Association (IATA) sets guidelines for cabin luggage/hand luggage/carry-on luggage size. As of 2022, the IATA recommends a maximum size of 56cm x 45cm x 25cm (22in x 18in x 10in), including protuberances like wheels, handles, and pockets. This can differ depending on the airline and aircraft model being used.

The carry on size suitcase they sell at the store fits in the overhead bin on most airlines