Taken from the website of a chemical supplier, the following solubility data can be easily obtained. Historically benzene and chloroform are commonplace for rotation measurements, however it can be any solvent in which the sample is soluble (or mixtures of solvents). You might be best to find a literature value for cholesterol (scifinder/reaxys) and then measure in the same solvent so at least you have a reference point to compare to.
One gram dissolves in 2.8 ml of ether, in 4.5 ml of chloroform, and in 1.5 ml of pyridine. The product is soluble in acetone, dioxane, ethyl acetate, benzene, petroleum ether, oils, fats, and in aqueous solutions of bile salts. Solutions should be protected from light.
Source Sigma Aldrich
Generally speaking, optical rotation isn't a method commonly used to determine whether or not you have a given compound. Methods like NMR, IR, MS, or even just TLC comparison are far more suited to this.
Optical rotation is useful if you already know you have the right thing, and want to know what your optical purity is like. Without having already confirmed that the sample is 1. clean and 2. the right thing, you'll struggle to make sense of the data since the polarimeter will simply give you a number.
Depending on where you bought your cholesterol from, and various other things, this number may be close to the literature value (maybe some confidence in it being the right thing), however even then you cant be sure its cholesterol as many other things will have similar values.