Should i take AP Psychology this semester or next semester?

If it is taken next semester, you can inform the colleges that you are taking it but the colleges will not see what final grade you get (unless you plan to wait to go to college and won't be sending applications until after finishing high school, in which case your high school transcript will show the grade.). If you want to show off your good final grade in it, take it this semester. If you think you'll get a D or F, take it next semester. (Note that some colleges may request a final transcript- but how likely that is, I don't know...)

If you are only taking this 1 AP class, *all* the others should be honors to make it look better to colleges.

May I strongly encourage you to take as many AP(and Dual Enrollment) classes as possible, 1 is being lazy on your part after being in IB. (Plus, getting college credit is rather nice.) Even if you don't pass the AP exam with the score needed, it will still look very good to colleges that you took AP classes, and the AP exam scores won't effect your admission to colleges. The more AP classes, the better, especially if you want to get into tougher schools.

I don't know if you took any IB exams last year, but to give you a sense of the difficulty level on the AP/IB exams:

standard level IB < AP < higher level IB.

My opinion: take AP Psych (and more AP classes!) this semester.