ephedrine products are safe as long as you don't prescribe to the if less is good, more must be better mentality... (which is very rarely the case when it comes to a healthly lifestyle, more is generally never better than a moderate or recommended amount of anything...)
just make sure you start and progress slowly... you may find you never need to take the maximum recommended amount (i never do)... make sure that you are drinking lots of water...
and as sassy said, cycle them in and out of your diet, they'll continue to be effective for you (by cycle we mean gradually reduce dosage after 5 or 6 weeks, go off for a couple of weeks and then gradually add them back in again... ) you may experience headaches if cut them out completely rather than cycling them out...
as for your exercises, its great that you are doing something! good work!
not sure what you mean when you say that you are lifting 15lbs...hopefully you are doing exercises for all different body parts and not just arms or legs... (remember to work your back and chest and shoulders along with your biceps, triceps, legs (quads, glutes, hams and calves) as well)
glad things are starting to workout for you... make sure you keep us posted...
phem