Is cognitive delay and retarded the same thing?

Sorry if i use the word retarded in my question but I was wondering if they are the same because I am autistic and when i was born i had to have a open heart surgery and then i have been diagnosed with 22.q.11 deletion syndrome and my mom told me that when i was 10 months behind cognitively when i was 18 months behind. and i was wondering if thar was the same thing? I also was walking at 13.2 months which is normal range but i am not shure about this?