I'm a 14 year old boy who used to be skinny up until the age of about 11/12, from then i started eating a lot more junk food and doing a lot less exercise resulting in some light man boobs and a gut. I am now 14 and have some weight by simply being more active and being a little more careful with what I eat over the course of about 8 months, though I still lack a completely flat stomach and complete non fatty pecks, though people would think me as skinny when i have clothes on (like a school jacket) it can be slightly seen when i am wearing a t shirt.

Anyway(sorry if that was to much exposition) I am currently around 175 cm tall (5'7) and weigh 65kg (143 pounds) and my goal is to have a flat stomach and maybe some light ab definition and some fairly toned pecks. so the workout regiment i decided to do was:

40 squats
30 push ups
25 squats
30 curls of 4 kg (8.8 pounds) weights on each arm
2 flat body planks for as long as I can

I run through this entire 3 times every weeknight plus i do about 1 and a half hours of mountain bike riding every single day of the week.
My diet is pretty average not to much junk food and and i consume a fair amount of legumes.

Should i change anything?
Should i do more cardio such as running?
Is it too much?
Is it to little?
Am i working out the right muscles?
Should i incorporate a diet?
Should i post some photos of myself or would that be unnecessary?

Any and all feedback would be greatly appreciated, thanks!