Rats are great pets and friends, good choice!
If your not sure about your responsibilty level, do more reasearch so you know what your getting yourself into. my favorite website is goosemoose pet portal - rat forum
Here is my checklist:
Are you willing:
to provide playtime outside of cage for at least an hour a day?
provide vet care if your rats get sick?
get more than one rat?
clean cage at least every 5-7 days? (some cages need it more often)
Provide good and nutrious food? (not all pet store food is sutable)
Provide sutable housing and toys? (rats are very playful)
Provide the about care for a rats lifetime? (2-3 years on average, sometimes more)
There are more than that, thats just what i can up with off the top of my head. im sure there are more you and other rat people could think of as well. The vet care is really the biggest thing. Of all my small pets, my rats need the most vet care. Sometimes they even need surgery. Also, the genders have personality differences, the females being more active than males, so be sure to pick the gender that best fits you.
I've owned rats for 6 years, and other small pets such as hamsters, guinea pigs, gerbils, and mice over the last 10 or so feel free to PM
me any more questions.