Well it depends. If you're not competing anywhere, then carry on. If you are competing affiliated, then check the website for the relevant body. If you are taking BHS exams, then no, it's time for a new hat.
A bit more information about your situation and somebody will pop along with the answer.
It's 3 years old and has been worn for one in-hand show and 2 dressage classes! Stored carefully in a padded bag on the shelf in my wardrobe. Will replace it for next year if we affiliate