I'm sure it is perfectly achievable but I really wonder if it is a good idea to have such a fixed idea about one date?
I flew gliders for many years and saw this happen several times, even to the point of taking the day off school. There was even a panic on one occasion about the time of day the person was born? I still don't know if, legally, that matters - arguably you are not 16 years old until that moment!
I don't have the slightest problem with somebody flying solo at the earliest possible age providing they are ready. I feel it is normally best if their first solo comes as a bit of a surprise with only a few moments notice, certainly that's how mine was. Is a huge self imposed pressure aiming for one day really helpful? There is nothing more unforgiving than aviation, always keep this in mind.