That means it’s a non-stiff ODE. Most of the time is spent setting up the stiff ODE solver which is never used. Change solve(prob, saveat = unique(Age)) to solve(prob, Tsit5(), saveat = unique(Age)) to hardcode a 5th order explicit RK method like is done in the R code. solve(prob, vern7(), saveat = unique(Age)) is also worth trying.
Note that one oddity here is that the R code has no error control on the solution, so 
it’s not an apples to apples comparison. To make it apples-to-apples, solve(prob, RK4(), adaptive=false, tstops = times), though I’d highly recommend not doing that and sticking to integration with error control of course.