Mostly a C&P from my other thread.
As the obvious and formerly open person I was back when I was 16, I told both my parents about it. They were skeptical at first.
When I was 13, I watched Gattaca for school. When relatives were over (including a tall non-biological uncle) the topic of height came up. I mentioned my height dysphoria and my dad jokingly brought up how Vincent from Gattaca got surgery to match a taller character he was impersonating. I said that I would be willing to get it if it was real. My dad was surprised.
My mom had a friend's son who got LL for dwarfism a while ago (probably external or LON/LATN) and told me I wouldn't want to do it, and even if I did she didn't think they would do it for "no reason" aka cosmetic. I then showed her Dr. Paley's CLL page. She hasn't shown any opposition ever since.
She told my older brother in college, I knew because before I ever mentioned it to him he already knew the typical gain was 3 inches, and that the doctors I wanted at the time (Mahboubian and Debiparshad) did it for $75,000. My brother later confirmed this. However, he kind of looks down on me for it.
Although my mom is controlling at home, she is always telling me that when I move out I can do whatever I want even if she doesn't approve of it. She also specifically told me it's fine if I get the surgery if that's what I decide I want to do.
My dad was more empathetic at first, knowing he was the one who passed me the "short" gene. He's always telling me how it bothers him how he passed short height on to me and that it bothers me so much. At first he was grossed out, but on my 17th birthday he actually got me to explain the entire procedure with the Stryde and everything. He still sometimes asks me questions about it, and once he even said he would come take care of me when I do it.
Additionally, I found out two days ago my mom is moving with my older brother for the rest of the year because he has a fall internship out-of-state (he asked). So there's a good chance she might also be willing to come take care of me for recovery.