Ageism is not an uncommon concern for those switching careers. It can work both positively and negatively depending on how you present it. The main thing is to make sure that you do not seem out-of-touch or outdated on your resume. Instant call outs could be things like "use of MS Word, WPM, etc". On the positive side, years of experience in transferrable skills, such as drafting (like you mentioned), and managing an independent studio show that you are seasoned and have good worth ethic and discretion. Do you have experience running a team, finances, managing stakeholders, etc? That's an angle that shows more managerial skill and perspective that a new grad typically doesn't have.

Do you have PE or P Eng (credentials are location dependent)? What kind of engineering are you specialized in? Do you have a portfolio?

At the top of your resume, you can have a sentence or two with your elevator pitch. Try not to keep it too fluffy and keep it concise and easy to remember. Some of the other life experiences can go in the cover letter. Interesting school projects can be added to a github or added to the bottom in an "Interests" section. (I believe that some of the newer tech companies are starting to ask for this).