SQL DB Question

Question

I'm in the process of designing a program to sell and Iu'm trying to decide what type of DB to use.  In the past, I built a program for my church and used an Access database.  I was thinking of using an SQL DB, but began to think, in order to distribute my program, I'm going to have to distribute SQL Server Express.  My problem is, if I build my program using an SQL DB, will the login info for the DB have to be the same if I use Windows Authentication as it is on my computers or will that matter?