You said there was a vote though? It couldn't get enough Dem's to even bring it to a vote. And no I don't think a majority of Dem's would choose to allow non adults to vote and it would certainly be dead if it made it to the floor. There are significantly more examples of Repub's trying to restrict voting since the 60's than Dem's trying to expand voting beyond groups of adults who were deprived from voting like women, African Americans, etc.