It's normal to feel pressure during your first 121 training event, for anyone. Few backgrounds directly translate to that, just because you may have been good at another demanding profession doesn't mean aviation will be easy.

At your age, age is a challenge, mainly the rote memorization aspect but also the multi-tasking. Even experienced pros will notice it after about age 45-ish. But plenty of folks get it done, you just have to expect that you'll need more study/practice time.

Also important to show up healthy: good diet, cardio exercise, and healthy lifestyle will help your mental performance (and stamina if you get an odd sim time). Omega-3 foods work for mental performance, eat some daily 1-2 months prior to and during a training event. Also brain games like lumosity, or even games/puzzles help. Video games will help your multi-tasking. Minimize the booze until after training, just because a 25-year old can do it doesn't mean you can.

If the first airline had domiciles which work for you I'd start there... if you can explain it right they might buy it that you're more motivated and have better perspective now. Worst they can say is no.

121 regionals are in the business of getting all-comers on-line, including retreads and low-timers. That's probably your best bet, turbine 135 training might actually be more challenging to complete, that's kind of a crapshoot. If you're looking for an intermediate step, maybe piston 135? But make sure you understand what the training entails.