Hi,
I applied for my visa too early. I put February 15 as my departure date, just as a guide. I wanted to get my visa approved before I spent all teh $$ on the tickets. They could not issue the visa for February 15. The ECO said they could not issue it, but would hold the application and docs as "pending". The visa will be issued closer to the date of departure. I told her we were thinking of travelling sooner than that. She just said to call her and let her know when we have our final travel arrangements. They can issue the visa 3 months before departure. We have now decided to travel December 22 so they should be able to issue the visa.
You should be fine. If your application is premature but otherwise in order they will just hold it as pending and issue it in due time.
Penny