It depends on the broader circumstances, especially career, of the individual.
If your career really is as a neurosurgeon then thus far you have done and awful lot of study and probably run up some impressive debts. But on the positive side the vast majority of your income is still ahead of you. It is thus reasonable to assume that such a person would have minimal cash or assets, but with lots of $ coming in they ought to be able to build them up in the years ahead.
At the other end of the scale, consider a tradesperson working on construction sites etc. If you are ever going to work lots of overtime then for most people the only real chance to do it is in your 20's. Same goes for jobs done for others on the weekend - by the time you're in your 30's it ceases to be an option to work 7 days a week. At most it might stretch out to age 35 or thereabouts, but it's very rare to find someone still doing it when they're 40. Future income is likely to be lower, not higher, in "real" terms unless you move into a supervisory or management role. If you haven't built up any assets by this stage then the odds are against ever doing so. Hours worked reduce and income goes down meanwhile a mortgage and kids come along - there goes any chance of saving serious money.
So it really depends on your career. If you are in a field where "real" income peaks in your 20's due to working long hours on wages, then you'd better have accumulated some assets before there's any kids (or even a partner in many cases) or it isn't going to happen. Reverse that if you're in a career where income doesn't peak until you're 50+.