100 Light Years From Home - S5-E19
Plot hole: At the end of the episode, Dawson is seated in the kitchen talking to Pacey in a normally loud voice. At the same time, Joey and Charlie are awake and talking in the pup tent in the living room, very close to the kitchen. Later in the Season we learn that Joey had no idea Dawson had driven down to Florida to see her, as apparently he left without seeing or talking to her. But being in such close proximity that morning; there is no way Joey would not have been able to hear Dawson's voice as he talked with Pacey. The living room was close enough to the kitchen, so it doesn't make sense that Joey wouldn't have known Dawson was there and if she did-she would have gone to talk to him.
Answer: It's only explained once in the series. Jack says to Andie "I tried to start kindergarten without you", meaning Andie was smart enough to start school early.