You are required to have reached age 70½ before making a QCD. A QCD does not require the distribution to be an RMD, so age 72 for beginning RMDs is not relevant.
A QCD can be made from any IRA, including inherited IRAs and Roth IRAs, but the QCD can be no more than the amount than would be taxable if all of the individual's traditional IRAs (if the QCD is from a traditional IRA) or the individual's Roth IRAs (if the distribution is from a Roth IRA) were fully distributed by year end. This means that a qualified Roth IRA distribution cannot be a QCD, so for most people this means that a QCD cannot be made from a Roth IRA or at least makes no sense to be made from a Roth IRA since the individual's Roth IRAs will be qualified within 5 years. For this reason, TurboTax does not support reporting QCDs made from Roth IRAs. Also, TurboTax does no checking to see if the amount indicated as a QCD exceeds the taxable portion of an individual's traditional IRAs if the individual has basis in nondeductible traditional IRA contributions.
To complicate things, now that there is no age limit for making traditional IRA contributions Congress added an anti-abuse provision to the tax code whereby if one makes deductible contributions in or after the year that they reach age 70½, a QCD cannot be made from the individual's traditional IRAs until an amount of transfers to charity that would otherwise be QCDs equal to the amount of such contributions has been made from the individual's traditional IRAs. (For this reason, if you plan on making QCDs it's probably best to not make deductible contributions to traditional IRAs in or after the year you reach age 70½.)
