There are two considerations.
1. The young adult has to have enough tax withheld over the course of the year to cover at least 90% of the total tax he will have to pay for the year. To do that all later in the year he would have to have very high withholding towards the end of the year, which might leave him with too little take-home pay.
Some people will tell you that you will not incur an underpayment penalty if you have a large amount of tax withheld late in the year. That's true because, for calculating the penalty, withholding is treated as if it was withheld evenly throughout the year, regardless of when it was actually withheld. But doing that is not practical for a young worker with little or no financial resources because it makes take-home pay very low towards the end of the year.
2. The person cannot claim exemption from withholding if he will have to pay some tax for the year, so he probably cannot legally have no tax withheld early in the year.
The young adult should use the Tax Withholding Estimator on the IRS web site to figure out what to put on the W-4 form that he gives to each employer.
My bottom line answer is no, he cannot wait until the third quarter to start having tax withheld. He should have normal withholding from each job during the year, and not try to manipulate it or game the system.
