Not to be the dark cloud here, but given you're age and a lifestyle that you are probably accustomed to, be prepared to rack up more debt as you progress toward a major career. I'm sure you already know this; your earnings will be near the poverty line as you build time through flight instructing. They will also be near our below the poverty line for the first year, possibly the second as well as you fly for a regional. Then when you are finally ready and have the time to progress to the majors, guess what? Another major pay cut.
I would say get the ratings first if you can't be talked out of this career. time is not on your side. I would think long and hard about starting into this at your age (no offense). You have YEARS to go until you're at a major, probably close to a decade. Please don't buy into the pilot shortage hype going on, that happens every 5 years or so in the news yet never seems to materialize.