new mac user needing help

I will be looking to get my first laptop ever but feel overwhelmed with so many different options. I apologize up front if I seem to long winded but I really want to make sure I make the right purchase.

I have always been a PC user with the most recent OS being Windows 7. Being in the military, I will finally be starting college however for the most part will be doing online school. I am looking at getting a degree in Humanities which believe will not be a factor for my computer needs due to the courses not having a high demand of computer program usage. Aside from basic web surfing, and college work, I will be using it for photography as a hobbyist and not for business. Not interested in video editing at all and not a gamer. I am also the average music listener.

With all that being said, I am interested in the new macbook pro 13 retina but on the fence about the 128gb or 256gb of storage space. I use an external drive for all my photography needs and since I'm used to that, don't feel a need move my photography to the laptop. I'm interested in purchasing this mac mainly for the photography but not sure if I'm thinking emotionally because of the aesthetics of the mac. Do I stick with this purchase and which storage space is recommended or do I go searching for a PC? Thanks in advance.