Rian Berlajolli

I need advice, I have a dell prebuilt office pc. It has always been my dream to make a gaming rig, and I need advice on a couple of things. I want to change the pc a little bit, so I want to add a dedicated gpu. 1660S to be exact (I saw your video on gpu's to buy in early 2020). I already checked the dimensions and it will fit in the case. I only need help with this: my motherboard is kind of old, considering that it comes in an older dell pc. It does have a x16 slot, so does that mean that I can put it there? Also, Should I change the power supply? it is a 250W psu. Anyone who I've spoken to told me that I need to check the compatibility of my motherboard with my card. But, as long as I see it, the only thing it needs to have is an x16 pci slot. I just hope you can help me and tell me what should I get, should I change the motherboard? Should I change the psu? Thanks in advance Rian