Should be playing D&D instead
Did B/X do training? I don't think they did, so in this case it's not a problem.Or stuff like B5 'Horror on the Hill' designed for characters levels 1-3 but you're likely to get dumped down the trapdoor and trapped in the three level dungeon at 1st level. There's a frickin DRAGON blocking the exit! If the PC's have the XP to level up in that dungeon, you're going to do it.