They've only taken in about 1400 new recruits in the new age bracket, so it's not like they've opened the floodgates to tired old geezers.
Certainly, the military is only going to seriously appeal to a small number of people in that age group. My concern is that lowering standards does two negative things.
First, it masks problems, rather than deal with them. The numbers look fine, so everyone assumes that things are going as well now as they were before. In reality, we have recruitment and retention problems that are being papered over with solutions like this.
Second, you can take a really good football team, sub out a random player for a girl, and do well. The team adapts and overcomes. You can sub out another player for an old man, and still do well. The issue is that at some point, you'll keep lowering and lowering the standards until it does hurt.
While we're not there yet, we should always be striving to raise the bar. Lowering the bar, and then patting ourselves on the back for doing so well, is an unwise trend.