Mac Mini not booting right away

Hello, Yesterday I tried to install windows with bootcamp on my mac mini, and when I tried to install it, it said that it could not be installed because the partition was not in the NTFS format. It said format but I did not know if it would format just that partition or the entire hard drive so I just completely exited out of the windows installation. When I tried to boot in to OSX 10.8.3 Mountain Lion after this, it would not boot right away. I searched the internet on my other computer and it said to hold down the alt/option key to get the partitions up on the hard drive to choose what partition to boot from. This worked and I was able to get into OSX. Is their a way that I can fix this so that it boots into OSX right away instead of holding down the alt/option key?