I bought my first horse earlier this year...a 10month old nonetheless. And to be honest with you, I don't think its really hit me that he is mine, and only mine, and nI have complete control over where he is, who he's with, what he eats, ect, ect.
Just go about it as you did before. Like someone else said, the only difference will be that you own her
Congrats and Good Luck!