Can't create a database in SQL Server 2012

I am a college student who is new to SQL Server 2012. I am trying to create my first database with this DBMS. Once I open SQL Server 2012 Management Studio I click the connect button to open up MSSMS then proceed to right click on Databases which is in the Object Explorer window which gives me the option to select New Database. I enter my Database name and leave Owner as default. I then change Autogrowth/Maxsize to megabytes instead of percent for both Database files then once I click OK I get this following message:TITLE: Microsoft SQL Server Management Studio ------------------------------ Create failed for Database 'CTU'. (Microsoft.SqlServer.Smo) For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=11.0.3000.0+((SQL11_PCU_Main).121019-1325+)&EvtSrc=Microsoft.SqlServer.Management.Smo.ExceptionTemplates.FailedOperationExceptionText&EvtID=Create+Database&LinkId=20476 ------------------------------ ADDITIONAL ...