6 week PUSH YOURSELF challenge

I would like to try this challenge...I have already told myself that I need to challenge myself to exercise more...Im 3 weeks into mfp and when I work out for about 20 of cardio, I am out of breathe and can't seem to go any further but I said I wanted to try to add just another minute or two, then five, etc until I can get to doing 60 minutes...Any other suggestions would be appreciated...I don't know if I can reach the goal of 350 minutes but I can certainly try....