How do i get to ascalon in guild wars prophecies?

Sounds like you created a PvP character rather than a PvE character. You cannot take level 20 characters created for PvP into the role-playing section of the game.

Start over or use another open character slot. Make sure you select for a PvE (Player vs Environment) character. This character will start at level 1 in pre-searing Ascalon. Then just follow the quests until you are level 7 or so and have completed all the pre-searing quests. Then you can take the quest to progress to post-searing and the main part of the role-play game.

Good luck, have fun!