My advice is to go in with a positive outlook. Make the best of your learning, and do your best to remember what you're taught. There are many opportunities within the Postal Service, look into all positions before you choose one. Certain careers are not meant for everyone
If you finish early as a rural carrier, you can leave and still get your regular evaluated time.
Of you are new coming in, you may not get proper training before management starts to move you around to other Postal jobs.