Top surgery, while permanent happens in cis women too and can be changed using implants easily. Plenty of cis females have small breasts. MTF Bottom surgery is a hell of a lot more invasive and complex. It involves the removal of the testicles, the removal the penis, and new structures created using penile tissue and skin graphs. A person would need to be in bed for at least a week to 10 days, getting up only to use the bathroom. They will also need the privacy to dilate every day. Dilation involves inserting a medical dilator into the vagina to keep it from closing. The process can be painful and messy.
If for some reason they are misdiagnosed and want this reversed, undoing that is a complex, multistage procedure, with follow-up procedures.
With that said, 15 seems like it’s a bit young to expect responsible after surgery care. It’s a highly advanced procedure that is probably right to be set for 18.
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