I dont think it is. Are you sure? Have your vet have a look next time hes there.My boy left most of his baby teeth in his manger for me, considerate of him. I have a molar with the roots ground down (thanks to my own dentist) and I wear it on a chain. My story is that it brings me luck! Mairi.
My youngster lost her incisor caps at 3 1/2 - she had to have some help as they got stuck - pics are below, but they are a bit gory! The vet had to come and remove them, and she had antibiotics as her gums were inflammed. She also had to have some molar caps removed as they got stuck. She is now 4 1/2, and I think has lost most of them, but she is still checked regularly just in case!
My pony's teeth didn't come out 'on schedule' my vet wanted to send her to the horspital to look into it, but I refused and they fell out a few weeks later.
The central incisors (01) should go at 2.5 like burtie says. The next ones (02) are the incisors in between centrals and the corners, which go at 3.5 and the corners(03) go at 4.5. This is the same for both uppers and lowers.
There are 6 cheek teeth; 06, 07,08,09,10,11 (excluding the wolf teeth 05). cap 06 is shed at 2.5, cap 07 at 3 and cap 08 at 3.5. The molars (09, 10 and 11) do not have baby teeth and usually the adult teeth start to erupt at 1 year, 2 years and the last tooth (11) in at 3.
I hope this helps but remember as from the above posts, this is a good guide and usually accurate but each horse is an individual and it is not too uncommon for the teeth to come through slightly later.
However, you will want to get your dentist or vet to take a look very soon as if you are right and the central incisors have not gone yet, they may be retained (stuck as the adult tooth may have come through on an angle and not pushed the baby tooth out). If he will let you at least have a feel if the central incisors are wobbly. If they arent at all - get an expert in sooner rather than later!