Darn, that’s a bummer, Stacy – disappointing, and so frustrating that they didn’t see your age or let you know about the by-laws early on.
How fitting, with the current Virgo emphasis, that a technicality, your age, was the reason for not admitting you…and, looking at your natal chart, maybe the current T Mars triggers to your natal chart (conjunct N Pluto; and inconjunct your N Sun-Venus) reflect the possibility of a difficult or unfavorable outcome.
Yeah, a letter or phone call to the Board Pres. sounds like a real long shot to me...but you'd at least know you'd done everything possible, if that matters to you at this point. Or, maybe focusing your time and energy on Plan B makes more sense? Take a day or two and you'll know what to do.
For those of us who have been concentrating on circumstances or challenges during this Saturn Retrograde period, I wonder if T Saturn turning direct on September 18, at 13 Capricorn, will reflect a less limiting or restrictive environment, in some way. Sextile your natal 13 Scorpio Neptune, could your hopes be more reachable and your efforts more easily accepted then?
After so much disappointment with your sister, it's nice to hear she came through with a supportive gesture. Good for her - and I'm glad for you.