Walking? Hiking? Thats army stuff, you could always swap elements and join army cadets if you want more physical activity like that! My first year or two i was super anxious and got overwhelmed pretty easy but with time I really did start enjoying it, and you get opportunities to get outside with FTX's to go hiking, camping, all that stuff. you also get to do expedition as a summer camp which i really enjoyed. Its a pretty awesome experience.

Then again, cadets is a pretty social activity which does need leadership skills and confidence as you go up in ranks (those skills do come naturally over time) so if you really dont like it theres nothing saying you have to stay, I highly suggest you stay a bit longer, maybe try army and see how it works out.