There’s a very simple reason for this.

In the January 2013 level 25 update, you got two buildings – Pimento Grove and Burns Manor. Pimento Grove unlocks as soon as you get to Level 25 on XP. There are no quests associated with it so you can build it right away.

To get Burns Manor, though, you need to have completed all the quests and built all the buildings before it. And even if your XP says you’re at level 25, you may not be for gameplay. This is because if you play a lot, visit a lot of friends, or house farm, your XP build up faster than your game level.

So, relax. There’s no bug or glitch even though you’re at Level 25. You’ll unlock everything else soon.