When to start preparing for the LNAT?

When to start preparing for the LNAT? Are there any Oxbridge offer holders who can tell me when they started preparing?

I took mine in the middle of September and I only started preparing in august I think (might’ve been July but it was definitely the summer holidays). I just did the free sample on the LNAT website and whichever websites I could get a free trial of, I didn’t pay for anything. (I go to Oxford now)