CADETorMID2018: congratulations on your LOA's.
Grevar: you have a right to be proud.
You both have a right to celebrate that accomplishment. Posting your status is appropriate. Getting an LOA (not to mention two) this early is certainly noteworthy!
But I also have to also agree with MHC123WC:
be careful not to appear to be gloating over those who haven't been so blessed. When my DS received ROTC scholarships, I did not hide that fact but added them to my tagline. When he received his USMA appointment, I added to the Appointment thread. I was every bit the proud dad that you are. That was my 'celebration' with others publicly. I think that is MHC123WC's main point.
I'm sure there are many 2018 candidates who are every bit as committed to serving as your DS, and who could qualify for an LOA but will not get one because there are only so many to go around. I think of another posters son who is now trying for the third time. There has been no LOA for him. Many will be so committed to serve, they will fund their own education and attempt to commission via OCS.
Please keep in mind that most of those who post or lurk here will likely see a "Qualified Not Selected" letter. They are going to wonder why because on paper they look every bit as, or more, qualified than many who get in - and in many cases they are. The admissions process will remain an enigma, wrapped in a riddle, surrounded by mystery (to paraphrase Churchill). I know that when my DS received the QNS Form Letter from the USNA, telling him to try again and work on improving his test scores and grades with challenging classes that the absurdity of that suggestion stung even though his first choice and dream had come through (he was a National Merit Scholar, AP Scholar with Distinction, 2200 SAT, over 4.x GPA, had multiple varsity letters and numerous EC's). The point is: many of those on this forum are as equally qualified as your son. So consider their feelings as you post.
MHC123WC knows first hand that getting in is less than half the battle; getting through is probably harder. He could tell you about the MIDs he knows who did not come back after Christmas of their own volition. He could tell you of those he knows of who were involuntarily discharged for one reason or another. Before he is done, 15% of his class will voluntarily leave because the academies are so much more than academics, accomplishments, and credentials. In the 2017 USMA class, nearly 30 cadets dropped before academic year. This from highly motivated, intelligent, kids just like yours who set their goal on a SA and endured the long admission process.
Celebrate today, but be careful about boasting because you don't know what tomorrow will bring, and what will change your circumstances. The cadet at USMA who is suffering with a concussion, or who tore an ACL in June and had to have surgery (getting DODMERD DQ'ed in June) come to mind. Those are just two examples I am personally aware of.
'Nough said.
I do wish you success in your future, and congratulations on having some clarity for next year.