Here's a list that shows the suggested level you should be for each zone in Dark Souls 2.
- Things Betwixt - Any Level
- Majula - Any Level
- Forest of Fallen Giants - [10-20]
- Heide's Tower of Flame & Cathedral of Blue - [30-40]
- No-Man's Wharf - [35-45]
- The Lost Bastille & Belfry Luna - [55-65]
- Huntsman's Copse & Undead Purgatory - [55-65]
- Harvest Valley - [60-70]
- Earthen Peak - [65-75]
- The Pit & Grave of Saints - [45-55]
- The Gutter & Black Gulch - [65-75]
- Iron Keep & Belfry Sol - [80-90]
- Shaded Woods - [80-90]
- Doors of Pharros - [80-90]
- Brightstone Cove Tseldora & Lord's Private Chamber - [90-100]
- Sinner's Rise - [95-105]
- Shrine of Winter & Drangleic Castle - [95-105]
- King's Passage & Shrine of Amana - [95-105]
- Undead Crypt -[100-110]
- Aldia's Keep - [100-110]
- Dragon Aerie & Dragon Shrine - [105-115]
- Memories of the Ancients - [110-120]
- Throne of Want - [110-120]
- Optional Area - Dark Chasm of Old - [95-105]