I transitioned into software development in my late 20's, and am very happy with the decision. I went back to school at ~27, and graduated just a few months short of 30.

34 is definitely not too old. While in school, I had classmates ranging in age from early 20s to late 40s. Everyone I graduated with is now employed and doing well. (Including those who started a decade later than either of us.)

Getting a 2nd Bachelor's degree in Computer Science worked for me. It only took 2 years, because I had a prior bachelor's degree, and it sounds like you'd be in the same situation.

Employers have generally been respectful of my prior experience as well (it was business focused, project management), so I don't think having worked in a different field is a bad thing at all.

Moreover, I work with plenty of software developers who started off in other scientific fields and made a transition to software more organically -- so it certainly can be done.

Ultimately, if you can pass programming interviews, you will be able to get a software dev job. It will be challenging, but you'll be happy you invested the time. Wishing you the best of luck!