I started flying three months ago and had similar concerns. My instructors recommended not doing a concentrated course as it does not aid long term retention of skills. I have booked lessons every weekend and found that flying once a week gives me enough time to think over the previous weeks lesson but isn’t so long that it makes me forget what I’ve learnt. Flying less than once a week I have found difficult, a couple of times I’ve lost lessons due to bad weather and coming back after two weeks its surprising what you forget. I guess it all comes down to how long you want to take to do the lesson, and how close you live to the airfield! Best of luck, I am loving every minute of it (except last weekends crosswind landing!!!)