Re: Age requirement?
I was 20 when I went to Stonington albeit this was almost 40 years ago now! I also remember a diver (Signy?) who was I believe 18, so there is hope. I don't believe age is too significant as long as you have the qualifications and experience sought and the right mentality and degree of maturity.
I spent my 21 birthday party in a screaming katabatic wind at the bottom of Sodabread Slope (North east Glacier) when the tent next to us began to disintegrate. We ended up with 5 people in our tent which also sustained storm damage but thankfully held up. Experiencing 100+mph winds when you are in a tent is rather invigorating!