Building any relationship takes time and effort. Don't expect to be best friends with your new stepparent overnight. If you have similar interests, and personalities that work well together, it may take less time to adjust. But relationships with stepparents can be hard because they may be "part friend" and "part parent."
Getting used to the balance can take awhile. Don't be disappointed if it the adjustment takes longer than you thought. Over time, you and your stepparent will both adjust.