Not at all my friend. I'm also planning to create one for my mother tongue. Only 1.2M people understand this language. Very small amount compared to German.
How many people understand german?

Not really limiting, it can help relate to your audience more.

First I wonder, why would you limit yourself since you do speak English as well.

But, if you want to address more the german speaking population it certainly won't limiting you since besides Germany you have Austria, Switzerland even further north there are also still german speaking people.

Creating two equal websites in two different languages can be a challenge and some work but it also would be rewarding.

There are also plugins for translation but they are not always very accurate.

Think about it if it would be worth to you to have two websites with the same content but in different languages.

Success always will take time. Just hang in there.

All the best, Viel Glueck

Sylvia