It's good to have goals, and DL is certainly a worthy one, but the vagaries of aviation typically make it difficult or impractical for most folks to target a specific airline successfully. They might well get there eventually, but at what cost in compensation, seniority, and QOL if they miss an opportunity to be employed sooner (potentially years sooner) at another top employer.

Keep your options open and don't hesitate to apply to most or all of the other top airlines. Also when you get to the point where you can apply, you'll know more... about what a competitive applicant looks like at that time, and how you stack up based on your school and training history, and other resume factors. The good news is that the top employers mostly all look for the same kind of stuff.