Not an accountant, but I'd do it.
28 and single, you have plenty of time to study, work, and enjoy hobbies. From what I've heard, it's much easier to pass rigorous exams when you are younger and not as far out from college. Even if it doesn't initially net you a big salary bump, it gives you an edge over some of your peer group and distinguishes you.
I studied for and passed a credentialing exam with a similar level of difficulty at 29 (last year.) After passing, my employer paid for my study material and exam fees and gave me a small (~$1200/year) raise. While not "worth it" on a financial balance sheet, (I studied for ~15 hours/week for 5 months) it has put me into a small group of employees that have achieved it, with 50% of them being in leadership roles.
The way I look at it is that it can potentially open doors and give you an edge-the market could tank for the next 10 years and we may not be able to achieve FI as rapidly as we hope, so I'll hedge my bets.