If you can afford it now and have all the funds, I would recommend to do it now.

Pro: possibly still easy. Rules will get stricter

Cons: you won't make the most of the 5 years validity

Just make sure the intended flight date and the course (if applying under soft power) is within the next 3 months. Even if you don't fly into Thailand until later, I doubt immigration will check. People's lives changes all the time