is always too far back. And I know that is dangerous is there any exercises to help me. My trainer took off my stirrups and irons so now I don't have those for a while to help me get my leg into position but any advice
If you have a trainer you should bring it up to him/her.
A good exercise is to get someone to put you on the lunge line. Remove your stirrups off your saddle and tie your reins. Focus on your position and you lower leg. Make sure you sink in your heals and your seat evenly. Work on your half halts etc. Carry your reins as tho you were holding the reins and keep your elbows supple.
Doing this once every couple of months will do wonders on your position.
I would put ur stirrup leathers down a hole because alot of times ur stirrups are too high and that pulls ur heal to far back because the higher ur stirrups the farther back ur leg.. also I would do alot of leg strengthing.. ALOT OF TWO POINTING... I use to have the loosest leg but now that I am with this trainer my leg is perfect cause all we work on is strength and everything else comes natural.