In the future, if I enter 11 words, and I sort through 12 words manually, will I be able to get to another wallet?
You can access it by
brute forcing.
The general rule of thumb is to keep 12 words safely. Offline, notebook, paper, or any backup that can easily be stored and kept.
Or will some kind of protection work and I can't just go further?
You can't access the wallet if you don't have the 12 seed phrase. Incomplete seed phrase = inaccessible wallet. If you are planning to randomly get some lucky wallet I'm afraid your chances are slim to none.