Just asked a girl out for food and she replied with "HM maybe, depends what time, since I have some plans"
what does this mean im not experienced in this stuff
It means that she has plans and wants to go out, but you'll have to work around her schedule.
Ask her when would be best for her - She'll either tell you, or deflect it (in which case don't bother.)
It means she's fucking chad
It means you are inadequate and she's already getting dick somewhere else.