Hello and welcome from Minnesota!
Thanks for sharing your GGMs quilt! You are so fortunate to have such a treasure. Take your time with it and find a mentor to help you. There are many on this board who know this pattern and would be willing to tutor you. As mentioned above, take some classes to get the "feel" of what you need to do and practice on some inexpensive fabric till you get comfortable with making the pieces! You'll be a pro before you know it! Your Mother and Grandmother will praise you for what you do with GGMs quilt! What a precious heirloom!
Please show us whenever you get it finished! Lots of luck to you!