Christine
I agree totally with what Anna has said. I have my 8th JY holiday booked for 2012, There is a rep at departures to greet you and make sure your in the right line for booking in etc. Most times the rep travels with you the one that will be doing the tour but not always. Not when I went to Tuscany or Austria, also they don't always travel back with you as they might be doing a different tour but they will get you to the airport and make sure your checked in etc.
You worry about being alone but you are in a group of people travelling, if you have to change planes your on that journey together, so I really would try and push these worries to one side and if there is a holiday you fancy BOOK IT and give it a go.
If there are any other questions please ask away and some one will be able to help you I am sure.
Good Luck
Cindy