I accidentally applied to Mesa College but it was intended to Miramar College.
The great thing about San Diego Community College District is that they allow you to submit one application per semester for the entire district, so there is no need to submit another application to Mesa College. You will still be able to register for classes at Miramar or any College in the San Diego Community College District for that matter.
Your initial submitted application to Mesa will suffice to all the Colleges in this District. Also, if you plan on taking courses at both colleges, I recommend you contact your Admissions and Records office and inquire about how to enroll for courses at either college or both if you would like.