Don't take an AI, take raloxifene. And no, neither will destroy your endocrine system. Honestly, if you're still growing height-wise, I've read an AI/SERM can delay your plates closing. More good than bad.
None of these are steroids, so you're not inducing hypogonadism and shutting off your testosterone. That's the big issue, not lowering estrogen with an ai or inhibiting estrogen from reaching breast tissue receptors w/ serms.
You'll be fine with either an AI or SERM. Neither will mess you up except in really rare instances. An AI will raise your T, lower your estrogen, and as long as you taper off you'll be fine. Ralox blocks the estro from your gyno selectively, raises t and estrogen very moderately.
Raloxifene is your best bet, though.
And honestly, if you haven't gone to a doctor yet... look up doctors on the internet that your insurance covers. Find one that's cool w/ steroid stuff and go to him. You'll be more likely to receive good care and an actual pharma serm script. Make sure you tell him it's not pubertal gyno and that it's from a test booster.