Not at all. I'm on the same boat as you but I'm way older: 34-year-old with 9 years of working experience as a creative. I love what I am doing right now and there are still room to grow for my career path. Originally I was thinking to pursue a master's degree in creative, however, I don't think I will get a lot out of school given that I work in the industry already, so MBA came into the plan. I am not a career switcher, but I think an MBA degree will help me to go on a management role down the road in ~10 years.
I plan to apply part-time MBA because:
1. I love what I am doing and I'd like to develop/grow in my current role without leaving my job (also because the job market is very tough right now).
2. I was finally debt-free 2 years ago, and I'd love to keep that financial freedom as much as possible.
I don't think you will be wasting your time and money, in fact, I read a lot about part-time MBA posts here, Reddit and Quora, most alumni had great experiences while attending part-time MBA programs. I'd encourage you to pursue it and think of it as a good investment for yourself. Plus, if your company is willing to pay you $5K per year and a total of $15K for 3 years? Go for it!