NEED HELP PLEASE Game Engine ASAP

[Texedova]

Hello, i have recently made a small team for game developing (just like 6 of us, me and my friends) and we were trying to figure out a good game engine to be used to create projects. I want to be able to program and modify the engine with c++. I wish to make an fps game or a rts. Also, if the game is good we wish to sell it and make profit. Thank you.