Full Push-Ups instead of Chest-Press


Hey FB-Family :)

In December I will start the program "FB Mass" for the first time cause I want to gain muscle / weight. I trained exclusively FB Hiit Workout before using their Programs, so I have the "Problem" that my Lower Body is really strong but my upper body not nearly so... when I'm doing Chest-Press with my dumbbells on the bench I can't feel my chest, even with (for me) perfect range of motion, my (thin) arms get more tired than my chest. I really feel my chest when I'm doing Push-Ups and Chest-Fly's, so my question is: Is it ok to start with "FB-Mass" and every time they are doing chest-press I will do push-ups... at least to the point where my arms are stronger than now...