Weigh yorself with its tack and then have a think.
Many people will say technically no, but as you are asking, are you happy with the equation? I wonder if some of these posts are requests for permission to buy the wrong pony for one's weight instead of thinking a) I could really do to lose half a stone or b) I am already the ideal weight for my height and to be slimmer would be dangerous - the pony is just too small...
Personally, I think there is enough disregard for their welfare and what is the real difference between overweight horses and ponies and the strain on their heart, lungs and legs and carrying weights well over and above what nature intended (which is none!). OK, so they carry the weight constantly when it is fat, but we canter gallop and jump for much of the time we are on board and often with little attention to warm up and cool down, or the 'going' (whose paddock isn't deep just now, or field rock hard - and roads have no give on any day of the week...)