EC help

Grade 11, i feel like my ECs are pretty shit. Peer tutoring, member of math and coding club since this year (no exec positions or anything), waterloo math contests and CCC. Play the piano as well but im pretty shit as i just started recently. I wanna get into waterloo math. Taking adv functions and gr12 compsci, have a 96avg and 97avg (although compsci mark should go up in a bit because i got a 99 on a test recently). But i hear about people with 97, 98 avg and good ecs getting rejected. Would i have a fair shot at waterloo math and how can i improve my ECs? Thanks