Great choice for a first snake! Doug is right; it probably won't be your only snake.
Sexing via probing or popping takes a lot of practice and experience to do safely, so it's good that you're not thinking of doing it yourself! Snakes can be hurt quite badly if you do it wrong. But many vets, and sometimes even reptile specialty stores, will sex snakes for you
Bacon is a great name for a rosy, by the way!