How young is too young??

My friend (age 15) has a boyfriend and she just told me that she has given him a blowjob and jerked him off before. I want to support her decisions but I feel like that’s way too young. Her bf is also 15. I’ve never had a bf so I don’t really know much about this kind of stuff. Basically what I’m asking is, is 15 years old too young to give a blowjob, etc?