Congratulations on your long-term success in beating severe aplastic anemia.
If you had radiation or chemotherapy before your transplant then those could be risk factors in your long-term health. Two other factors are good news: you didn't have a problem with GVHD and you had your transplant when you were young.
The longer you go without any reoccurrence or new disease, the closer your life expectancy returns to normal. According to one study
it takes about 30 years post-transplant before your life expectancy is completely normal, but that study covered many diseases and patient ages.
If your health is fine now then your future looks better and better every day!