Activities are stored in the FIT format, which is publicly documented and they have a rather easy to use sdk available for it as well[0]. Its fairly trivial to get other daily metrics out of the watch as well using Connect IQ, you can even write out to a plain text log file if you want.
Keep on trucking. I started working full time as a SE when I was 16. The job provided a nice relief from highschool and helped build up good working habits before I left for college. If you are interested, see if your school would be willing to allow for a work study so you would be able to pursue such things during the school year.
If you dont like how they implemented it you could easily write your own, the api is fairly straightforward: https://developer.garmin.com/downloads/connect-iq/monkey-c/d...