18 credits will too much

I will start as a sophomore this fall,
I already took 15 credit hours,I looking for another class to add ,like Introduction theater.
My class are
Cal 2 =4
Microeconomics =3
History 2 =3
Pols 1 = 3
Chem Lab (1+2) =2
if add one more class,it will to hard to carry???

How can you take a Chemistry Lab without taking the accompanying Chemistry Lecture class? You generally cannot take just the lab portion. I would first research whether or not you are going to be dropped from the lab for not taking the lecture that goes with it.

Whether or not 18 hours will be too heavy of a load depends on how difficult and time-consuming the classes are for you. I took 18 hours several semesters when I was in school because I absolutely had to finish in 4 years and sometimes it just worked out that way.

You can always sign up for 18 hours and go to classes for the first week and then figure out if you need to drop one of the classes. You will only get a partial refund, but as long as you drop before the census date, it will not count as one of the 6 permitted dropped classes.