This is awful advice coming from someone who went the road of the OP.If you have the CV now to match into what you want you to do go forward with it. There is no need to slow down because you are younger than the rest. You will finish training earlier, earn more quicker and be in a position to have more flexability in career choices. In terms of missing out, again I disagree. At 23, I might have been on nights but when I was off, I enjoyed life just like most of my fellow interns did with immature fun. The value of a research year if you are already competitive enough is limited and unless you want to go into administration an MBA/MPH has limited value in my experience.
I would argue the increasing age of entrants is a bad thing not a good thing but obviously I am biased having gone the short route. If physicians can practice for longer, part of the so called shortage disappears. Physicians are able to earn more as they work longer as well. It was far easier to get through the nights and pain of residency being younger and being able to not have the pressures of family planning, etc. since I was young enough to forgo this while training and still be reasonable young at the end.