Again, because you're all so caught up in your Hillary dreams that you can't bear to see any different opinion that might shatter that reality.
It's one thing to say that she can't win because of the ideas/values she has, but to attack her for her age when history proves otherwise is just trolling. Sexist/Ageist attacks against any candidate, regardless of party, is immature and unproductive.
Also, Ronald Reagan didn't have the historical aspect of his presidency/campaign such as Hillary will, which increases the likelihood that she could/can win.