Four teen-agers have been arrested on suspicion of making $23,000 in counterfeit money with a sophisticated color copier, police and Secret Service agents said. Three of the teen-agers, two boys and a girl, were arrested Tuesday after spending a weekend at Disneyland and in Mexico. The fourth youth was arrested at Disneyland last weekend when he allegedly tried to spend a phony $100 bill. All four suspects are students at Meadow Park School, a court-run school for problem children in Novato, Marin County. The teen-agers told police they successfully passed two of the fake bills.