Kudo’s to you for taking on the job of building something that you and the next generation will be proud of. As others have said, the thing about building is not how BIG you can make something, but how well something should be done. From the proportions and sizing, to the location and siting . Attention to detail. Take just a little time to get the details correct now, and you will be happy for the rest of your life.
I appreciate your taking the time to think about how it is going to fit into its surroundings, and how it is going to work in that situation. And to making something that will stands the test of time.
We look forward to seeing your project to completion. Thanks for sharing.