Welcome to the community, Linda! While Airtable doesn’t natively support conditional logic that could make a text field become visible if the “Other” option is chosen, you can still put a text field as the next entry after that selection list, including a comment that the student should use it to explain their “Other” choice. They can still opt to leave it blank, though, so it’s a gamble. You could make it a required field, but then it would become a minor nuisance to those who don’t need it, so I guess you gotta pick your poison.
FWIW, there are third-party form tools that can integrate with Airtable, and which do support conditional logic. Check out On2Air: Forms by @openside if you want to go that route.