DESeq2 Not full Rank – Age & Medication

Hi. I’ve a data matrix which looks like this:

I’m trying to carrying out DGE analysis controlling for age and medication so I used the following:

design(ddsMF)<-formula(~age+medication+group)
ddsMF<-DESeq(ddsMF)

And end up with the error, “Full model matrix is less than full rank.”

I saw the vignettes on the DESeq2 tutorial but am not sure if they would work here given the large age range. Any advice would be most welcome.