Hello to you and welcome,
There really is nothing to worry about you will have a great time I am sure. I have not done the Lake Garda tour but it is very popular I understand, so I am sure you will get some feed back regarding it.
I have done 7 tours with another booked for 2012. They have all been good for a variety of different reasons, but along the way I have encountered a great bunch of people from all ages and all walks of life. You will be fine.
Cindy