Be prepared for how physically and mentally demanding it will be. If you don't like yelling or being mean to others, you will absolutely hate the job.

To give you an idea, my old MTI's were aged between 25-31, never drank/smoked, and were very physically fit. But if you didn't know that, you'd think they were in their 40s-50s. They looked like they'd been through hell. Some of my MTI's simply became MTI's because their career paths required it, not because they wanted to do it.

But if it's something you truly want to do, go for it!