That depends on your age and maturity level.
When is it okay to start cuddling? We've gone on two dates and for the third he's coming over to watch a movie and he suggested cuddling... Does that sound normal/okay?
Graduate High School then cuddle, with good reliable birth control.
Seriously ... Unless by "cuddling" you mean holding hands, or possibly his arm around you ... It's 90% unlikely you will stop at "cuddling". And the only way you are "mature enough" to handle the responsibilities risked by going further, is if you have a "family wage" job.
Birth control is not guaranteed.
I'm not sure if cuddling is cuddling or something else, so before your decision, and for your own protection let me present you "both" with the following......
If u r ok with it and If it gives u good feelings, Its completely normal. Go for it.
