(First of all... read my original disclaimer AGAIN and apply it here as well). Now for my response....
Then how could ANY of us tell you it is worth it!? There are many on here that fail at this and many succeed with only some maintaining at goal weight. Only you can know, based on your understanding of your food challenges, medical history, etc. if the amount of money is worth it for YOU. When I see people getting 2-3 surgeries and still struggling, I know that the real issue was that they didn't seek assistance for food issues prior to getting surgery. There are even those with DS that have never reached goal.
For example, why would I come on here and ask if I should get coronary bypass surgery? Only I know if I will be committed to following dietary restrictions, cholesterol reduction protocols, etc. Otherwise, what is the point in having it? The nature of your post placed an $18,000 price on your life and then you asked us if it is worth it?! How could we possibly answer that! For me, it was absolutely worth it! It paid for itself in one year based on the elimination of all of my co-morbidities. Yet, you can ask a poster on here (who had 7 coronary stents) and she would tell you she regrets getting weight loss surgery. Yet, with her history, she probably wouldn't be here today if she didn't have it. Yet, she still regrets it.
So, while my response may have sounded harsh (and re-read the disclaimer before I started), how could we possibly advise you on the value of your life?! Did I tell you never to get surgery? No! I made a recommendation, that I clearly stated should probably be followed by all seeking WLS, to have counseling and support group FIRST.