Shit like this is why I don’t purchase until I can afford the entire build. Time goes by faster than you think. It would sick to get stuck with a PC that’s already obsolete before you get the funds together to finish it.
If I were you, I’d return everything while you still can, then set aside the money until you can afford tje complete build. Luckily for you you just started, so the return window for everything will still be open for everything.
Consider this a lesson learned and good luck with your eventual build!