Do you intend to rest during those exercises or are you aiming to do 50 pushups etc. in a row? I think you could try doing regular pushups earlier than that. As for squats, can you get down below parallel on your own? If so, you might want to throw one deep squat in every 10 reps or so since bench squats might strengthen your legs but won't help you to go deeper. And again, 50 is maybe a little too ambitious. I love my quads and think I'm in pretty good shape but I can't do much more than 30 in one go without basically resting for a second between each rep. Planks look good. How much weight will you use for overhead presses? If you can get 25 reps out, then you need something heavier. Try something that you can get 8-10 reps per set with, or 5-8 if you're feeling like an animal.
That routine looks like something you could do 3 times a week.
You lousy kids! Get off my savannah!