Since you are trying to make a Roblox game, you have no other option than to use Lua, since Roblox only allows coding in Lua. Yes, you've heard right, Python is identical and as easy as Lua, although Lua is easier than Python. Beginning from Lua and then escalating to Python is recommended. Java is only helpful when you are creating a heavy, big-budget, enterprise-level product, otherwise, Python would suffice.