In the poem, the narrator presents her feelings about growing old in a humorous and upbeat manner.
She portrays the idea of growing old as a period of great freedom. During her sunset years, she will no longer need to adhere to societal expectations for accepted behavior. As she presumably will have little responsibility for anyone but herself, Joseph maintains that she will be able to engage in activities that were previously considered socially unacceptable.
For example, the narrator looks forward to wearing clothes that don't match, just for the fun of it. She looks forward to spending her pension on frivolous items and later complaining about having no money to buy nourishing food. She maintains that it is the province of the elderly to do outrageous things, especially if they were responsible figures in their younger years.
The narrator looks forward to making up for the "sobriety" of her youth, learning how to spit, putting on weight, eating whatever she pleases, and learning rude manners. She revels in the idea of being able to sit down wherever she is, if she happens to be tired. For now, though, she believes she has to act respectably; after all, she must "set a good example for the children."
Despite wanting to set a good example, Joseph muses that she should probably start to "practice a little" these odd new ways she will take up in her elderly years; otherwise, people may be shocked when she is old and suddenly begins acting contrary to her present behavior. In all, the narrator presents her feelings of growing old in a lighthearted and upbeat manner.