I was in Girl Scouts from the time I was 5 all the way through high school and I can tell you, it was so worth the experience. It helped me build my self esteem, confidence, sense of responsibility and respect for myself, others and the world around me. I am now a lifetime member of Girl Scouts and have some wonderful memories of my times as a youth in scouting. I even met my best friend at summer camp when we were 9 and we are still close friends today. Girl Scouts kept me focused through school and gave me a place to belong. I know countless others who have had similar experiences.
If there is anyway you can let your mom support both you and your daughter in this venture into Girl Scouts, I strongly encourage you to do so. There are so many opportunities for your daughter to explore, and she will become a better person because of it! :)
Once your daughter gets started, it's possible that you can arrange for your daughter to be part of a carpool if driving becomes too much for your mom. Maybe she can drive one Saturday a month and another mom can drive the other Saturday a month. Also, chances are that there will be activities throughout the year that will happen on other days besides Saturdays that you can participate in as well.
Talk to the troop leaders. They are your best friends! :) Ask them if there are things you can do "behind the scenes" to help support the troop. Maybe you can help prepare the weekly crafts, or help plan a special activity that happens on another day besides Saturday. Could you make a snack for the troop once in awhile and send it with your daughter? Would you be willing to host the troop at your workplace one Saturday and show them what you do? There is always work that needs to be done to keep a troop functioning, and it doesn't always happen on meeting day. I'm sure that the leaders would be grateful for your help. Parent involvement doesn't just end with driving your daughter to and from the meeting!
Good luck, and I hope your daughter enjoyes her time in Girl Scouts!