It can be grammatically correct, but it might sound awkward:
* Correct: "Often, I go for a walk in the park."
* Less awkward: "I often go for a walk in the park."
Consider these points:
* Emphasis: Starting with "often" emphasizes the frequency of the action, but it can sound a bit repetitive.
* Flow: Putting "often" later in the sentence might create a smoother flow and avoid a jarring start.
* Style: The overall tone and style of your writing will influence whether it's appropriate to begin with "often."
Here are some alternatives to starting with "often":
* "Frequently": "Frequently, I go for a walk in the park."
* "Regularly": "Regularly, I go for a walk in the park."
* "Many times": "Many times, I go for a walk in the park."
* "I go for a walk in the park on a regular basis.": This is a more formal and concise way to convey the same meaning.
Ultimately, the best way to use "often" in a sentence depends on your desired effect and the specific context.