Score based battle system, how difficult (for a total beginner)?

Hey newbie here,

first i hope im posting in the right category! My daughter loves games like Love Nikki and Mr Love so i wanted to make her a special present for her birthday in August next year or well at least im trying to.

I checked these games and they both have something like a scorebased "battle system"(?), they select some cards or outfits and the person with the highest points wins. Im trying to get something similar for her game but the question is how difficult would it be for a total newbie to write a script for it?

Or are there any tools or something to assist? I couldn't really find an answer and im not even sure how to describe it best so i hope someone could help me with a bit of guidance where to start best.

Thanks in advance