Get the medical out the way as soon as possible - you never know there might just be issues,
then get the exams done, other than the weather it is the surest way to find they are holding you up from completing your training,
Talk to as many pilots at your intended airfield as you can to establish the best training organisation to use,
Never pay them for the whole cost of the course however attractive the package may seem,
Make sure you have set sufficient time aside allowing a lot for lessons cancelled due to weather to ensure as others have said you do not have to keep relearning the same material,
Add Avgas and enjoy!