Worried about adult and baby guinea pig?

I got a baby guinea pig recently because my other guinea pig died. We originally had two guinea pigs but when Pearl died, Amy was left on her own. We were advised to get a baby guinea pig because Amy was a caring guinea pig. After getting the baby guinea pig (Gracie), I noticed that she was suckling Amy. Amy doesn't like it and I'm worried about it. Gracie's 10 weeks old and Amy's 4 years old.