Do it.
I took 5 years off. I got to move to a new city, be a "real" scientist, try my hand at business, law, and advertising, got a handful of publications, and even fit in a graduate degree and plenty of volunteer work. I learned to ski, competed in my first triathlon, and had plenty of time to go hiking and camping. I partied like a rock star five nights a week, and still had enough money to go on kickass vacations all over the world. I made tons of new friends, of all ages and from all walks of life. I learned to do my own taxes and balance my checkbook. I saved when I needed to, and I splurged when I felt like it. I danced, I drank, I lived, I loved, and I have absolutely no regrets.
If there's any doubt in your mind, take some time off. Get it out of your system. If you're like me, you'll realize that you weren't ready for medical school at 21. True, I'll be starting my program at 26/27...but I wouldn't change a damn thing.
Oh, and don't worry about alleged "age bias." It doesn't exist. There's plenty of proof right here on SDN. 🙂