Hi Randi- how long did you let the mother sit before using it and what did you make it out of?
If your mother was fully developed, making the cab into vinegar should take about 60 days or so in a cool place. How it will turn out is dependent on how much mother vs how much cab you used too- if it is thin or weak, add some vinegar. If it is too strong, thin with a little water.
You can actually use JUST wine to make vinegar too- you can pour wine into a crock or glass container, put cheesecloth over the top, store at about 60 degrees and in about a month it should be usable.