Will you be using the free Student license of Ansys that has model size limits or will you have access to a full license that has no model size limits?  If you are on a full license, it would be better to have more RAM. If you are on the limited, free license, you will be okay with 16 GB of RAM. That is what is on my laptop and it is fine.

Note that it is easy to install more RAM later, but the CPU is not easy (or maybe impossible) to upgrade.

Higher clock speeds are better.  More cores may not be useful if you are on the free Student license, which is limited to 4 cores.  If you are on a full license, you also need an HPC license to use more than 4 cores.

Ansys can use most OpenGL graphics cards for Display.  Ansys is very particular about the make and model of the GPU card used to accelerate computation. These cards are costly and since you are just starting, I would suggest you not spend money on an accelerator GPU since you have a tight budget.