Sorry if I posted in the wrong subforum, wasn't sure where it needed to go!

I made a 3D object but it's one meter atm and I need it to be 5cm (I will need to print it irl in a few days...). However when I try to resize it with sketchup it completely deforms the object and it looks awful...

How do I fix this?

I'm a total beginner (I started yesterday) and I don't want to remake everything, I'm not even sure I can do that....

Thank you very much in advance!