If you have 1-3 years programming experience, then look at a game engine.
If you have no or little programming experience, then you need to make several single player console application type games such Tic-Tac-Toe, Crossword Puzzle, Pong, Pac Man, Asteroids, Defender or others, which display to screen in a window or direct to screen. "Hello World" or something similar should be your first attempt / test run with this. It would be ideal for the lead programmer in your group and all others to also have 3-5 non-game applications made, such as randomizer, GUI, indexer, timer, search box, and so forth. This will keep your team busy for at least several months. Understanding the coding is far more important than speed!
Since your team is beginning level, you should choose a relatively beginner friendly language such as C#, Python, Ruby, Lua, etc. ONE language is what you focus on achieving to intermediate level before adding a second language! It is perfectly fine to choose a 2D game engine or 2D version of a game engine and a high level language to program in it, even if that language is custom created for that game engine. All custom game engine languages are relatively similar to at least one major standard language, so switching to the relative language would be fairly easy later.
List of Game Engines