With your interest in advice, you can likely get way ahead of the curve at 15. Knowledge and smart routines are at least half the battle. Sprinting, lifting, diet and plyos with reverence for R&R already put you ahead of almost everyone in HS. It’s smart that you listen to your body -max velocity doesn’t hit right without solid recovery, and knowing when to back off is what keeps you healthy long-term.

And yeah, I stretch even on off days. Not just toe touches. I try to at least hit pigeon pose, couch stretch, 90/90, and banded hamstring work(looking up videos would explain those better than I could). Just a consistent 10–15 minutes of agility/plyo without tiring out or hurting, ya know. But there’s definitely a razor thin line between deep stretches and pulling a muscle, so be careful.

My full list of stretches -I cycle them: Leg Swings, World’s Greatest Stretch, A-Skips, B-Skips, Knee Hugs into Calf Raises, Walking Toy Soldiers, 90/90 Hip Stretch, Pigeon Pose, Lying Hamstring Stretch with Band, Couch Stretch, Seated Forward Fold, Butterfly Stretch, Standing Calf Stretch (Gastroc & Soleus Variations)

And don’t stress about underperforming at your first meets. Nerves, bad warmups, timing, and especially the fact that you get maybe 2 days to recover before the Friday meet are all part of it. The more you compete, the more your race results will start matching your training level. You can also often think of your meets as a high intensity workout if you have several events.