If you know a little of C++ and C#, why not try them both out and see which you like the most?

Both are very competent solutions, and have different approaches. One may resonate with you and you might use it and think "ah ha, yes, i understand and enjoy this".

You may find you like both equally as much, and then you've gained a ton of knowledge.

You can't really go wrong though, there is no bad choice here - both will be suitable for creating a first game.

Regardless of where you feel more "at home", unity has more documentation and a metric ton of "premade" game and asset examples on their store to learn from.

and if you're new, it'll take some days until unity start charging you for your game's sales.