I'd start the process of breaking at 3, and I think it might be a bit of a stretch to reach 14.2hh as pony was highly likely to have been born spring/summer, so its probably already nearing 3, and if only 12.3hh now, it would have a lot of growing to do x
We have a NF x small pony who is exactly a year older and I'd say in the last year she has grown about 2 inches. We're expecting her to end up at around 12.2hh but then she might have a late spurt and be 13hh.
You can start work on breaking at 3 but be careful not to do too much as the pony will still be growing and esp if she's being broken by a small adult who will be proportionately heaviier than a child might. We're not going to break ours until she is 4 as younger son is not ready for her anyway.
If i remember correctly my nf gelding was around that height as a rising 2yr old, he is now around 14hh and still bum high. I am hoping he will finish at 14.2hh he will be broken this year as a four year old as he just was not mature enough as a 3 year old.
IMO 3 is too young to break a NF, they are slow maturing ponies. I own a rising 3 year old NF and he won't be backed until he is 4, just to give him the extra time to grow into himself more. I don't think your friends pony will go to 14.2hh, my 3 year old is 14hh now so he should definately make the 14.2hh mark. I'd say your pony will be 13.3hh max.
It's now 3 years later.
What did your friends NF reach?
I am assuming he is nearly 5 now?
(Terrible at math lol)
I ask as my NF filly was out of a 14h NF mare and a 15h NFxCob stallion.
She is a rescue, however at 2 years she stood at 12.3.
At 2 and a half she is now 13.1.