Is it normal to not know how to swim?
Mostly.Normal for most people
Yes. Plenty of people never learned to swim, and it’s nothing to be embarrassed about.
Swimming is a skill, not something everyone automatically picks up. You may not have had lessons, access to a pool, or a comfortable chance to learn—and lots of adults are in the same boat (so to speak). People have different feelings about it, but not knowing how to swim isn’t a character flaw.
If you want to learn, beginner lessons are a perfectly normal place to start at any age. Until then, stick to water where you can stand, wear a life jacket when appropriate, and don’t let anyone pressure you into swimming beyond your comfort level.