Sixteen and 17-year-olds will be able to vote in the next assembly election under plans outlined to AMs.
Talks will also continue with the political parties about expanding the size of the 60-member institution.
Presiding Officer Elin Jones said increased pressure and responsibilities in Cardiff Bay meant action was needed "as soon as possible".
The assembly will also be formally renamed a parliament before the election in 2021, she confirmed.
It follows the McAllister report on the findings of an expert panel, which said last December the assembly needed 20 to 30 extra members to cope with its growing workload.
On the final plenary day before the summer recess, the assembly commission - which handles day-to-day business - published the findings of a public consultation into the recommendations.
Ms Jones said: "As the chair of the expert panel concludes in the report, the assembly cannot continue as it is without risking its ability to deliver for the people and communities it serves.
"We now have the opportunity to make our parliament a more effective, accessible and diverse legislature; to forge the national parliament that the people of Wales deserve to champion their interests and hold the Welsh Government to account."
Analysis by Vaughan Roderick, BBC Welsh affairs editor
The decision by the commission to split possible reforms to the assembly's composition and voting system into two separate packages is a recognition of how potentially contentious some of the proposals could prove.
The first package contains reforms around which a broad consensus already exists.
While some AMs have reservations about votes for 16-year-olds they're unlikely to fight too hard against the change for fear of alienating younger voters.
Similarly there's broad support for changing the legislature's name to the Welsh Parliament.
The second package of reforms concerning the size of the assembly and its voting system is likely to prove more controversial.
The Welsh public will take some convincing if they're to believe that more AMs are required in Cardiff Bay and Labour will be reluctant to embrace any voting system which dilutes the advantages they enjoy under the present arrangements.