The only issue is whether or not you can psychologically handle living with a load of 18 year-olds and cope with being at the bottom of the pile for a good while. You'll get peed off with the total idiot teenagers, and shown up by the mega-switched-on ones.
I don't know where you are in your life, but at 24 (if you are settled and have a family) it might not fit with your domestic situation to go off and get ratted after you pass out and come home with a tattoo of an evil clown on your arm.
Had a lad join us at 26, fit and capable, 4 years on hes leading his own section in Afghanistan. Theres no substitute for maturity, show a mature attitude and you'll quickly start to distinguish yourself from the pile.
You will start off with guys younger than yourself immediately in positions above you, but hard work will see it even itself out over the years.
Back in 84 we had a 26 year old spotty ex foundry worker geordie join us. He was an 18 year old with 8 years extra smokers cough added. Poor lad needed gripping by the 18 year old often. He ended up as a genuine Bill Oddie Storeman!
I've done 5 and a half years in the navy so far, (commando helicopter force) but wanted a change. No family commitments back home. Might think about the officer path rather than non commisioned. Cheers lads.