The MBTA’s top official is urging the agency’s board to delay any fare hikes until the summer of 2019, but commuters could still face higher fees at some T parking lots far sooner.Staring down a $100 million budget gap, members of the T’s Fiscal & Management Control Board aren’t ruling out fare hikes in January despite General Manager Luis Ramirez’s recommendation that “we start this process next year” and push any potential hike to July 2019, for the start of the following fiscal year.