Both Google Sheets and Excel save dates as numbers (day counts) starting on 1900/01/01. As a result, they either automatically assume the year for you or fail to detect the date at all. Date to number conversion: 1900/01/01 = 1, 2023/01/16 = 44942 (because it is 44942 days since 1900/01/01).
People born in this year can't, in my opinion, complete the survey, so just "filter" them out:
If date is in A1 use the formula:
I hope this helps you.