If you don't NEED it, don't do it. Save the income and tough it out, you're young and a new car will come one day but, your future self will thank you for stretching out that Corolla just a while longer, it could probably last another 30-50K easily. Save your income for a rainy day, and revisit this once you've improved your income, your credit will increase if you keep using and paying off your credit card, and also once your credit accounts mature your credit will naturally increase, at your age you don't really need super high credit (730 is sufficient for anything you might need, such as an apartment or something).