Either Ideation or Prototyping because those are items that you create after you gather sufficient informations about the users and business goals - hence, you have a good idea what you want to create and you are planning for it.
Hey man I used to do trades but I want to change my career I don't have a college or university degree I need the truth I'm not a baby how likely is it be able to get into a ux career learning myself and making my own portfolio
Truth is you don't need university degree, and you can enter the field entirely through self-thought - I'm the best example of that. I don't have degree in the field, and I learn everything by myself. That saying, everything will depend from your own work you will put into this - but I know people who successfully changed their career after 30s, even 40s.