It's looking more and more like Delegate Jill Carter is right, they do not yet have the votes:

The chairman of Maryland’s House Judiciary Committee says he will likely delay voting again on a bill to legalize same-sex marriage.

Delegate Joseph Vallario, D-Prince George’s, said Thursday that his committee has a lengthy list of bills to hear and is not likely to have time for a vote on the high-profile bill.

... House leaders have had trouble finding support on the committee for the bill and have spent the last two days lobbying members. (source: The Associated Press)