When should I form my club idea?

So I wanted to make an App Development Club at my school so kids could join and make their own apps to “change the world.” I am currently creating a School GPS App using swift (not getting into too much detail) and it’ll be finished by the end of this year. I definitely have enough experience to make this club next year, but I don’t know when to do it. Should I start it as a junior or start it as a senior?

Oh yeah I’m currently a sophomore

If you’re going to be finished with the app by the end of this year, then I suggest start the club as a junior so you have more time to spend in the club (two years as opposed to only one year).

Definitely start it as a Junior. As you develop your app, document the steps you took to do it.
How did you determine the need?
How did develop the requirements (what the app should do)
How did you choose the app development platform?
How did you learn to code?
You will want to be able to work with novices and people with more experience.

Talk to your CS teacher about being adviser to this club.