Hello-
Starting a new job in the year of your b-school applications is not an insurmountable obstacle - I have worked with many successful applicants in your situation. And if the new job helps put you closer to your career goals and/or is a title/compensation increase then it can even be a positive to your application.
You will likely not be able to secure a letter of recommendation from your new employer since you will not have been there very long, so it will be imperative that you are able to secure one from your most recent (i.e., current) employer. An specifically, from someone who was in a role to evaluate your work.
Another way that it could hurt your application is if this is your third or more company since graduating from college. Business schools would prefer to see promotions and career progression within one firm, so if you will have then three or more companies on your resume you might have some negative "job-hopper" associations.
I hope that helps and good luck!
Best,
Heidi