In southwest Florida it is almost impossible to fly any amount of time without occasionally encountering rain. My first time was on my long cross country solo, and it continues to my last time yesterday. If I am flying IFR, I try to avoid moderate or greater, and anything that has lightning of course. ATC here is really, really good about allowing deviations, and in fact usually offers it before I am even thinking about asking for it. If VFR, if I cannot see through it then I avoid it. If I can see through it(appears on Nexrad as mild) then I will fly through it. Otherwise I will deviate. I have taken off in rain, and landed in rain, and have not had any problems. When landing in rain remember your roll out may be longer, and being as conservative as possible is imperative. I am not big on using brakes to begin with, and use them for stopping as little as possible. On wet runways I use them even less, and then again very, very lightly.
Bottom line, be careful, and if you are not sure then do not fly, or go with an instructor.