Certainly you could mention it as an offhand every so often, but the important thing IMHO is to make clear that you're looking to improve your English skills, as opposed to apologizing for whatever flaws you might have in your English.

The latter is usually needless, and can even imply that not knowing English well enough should be a source of shame, which is why it often draws calls saying not to apologize. It'd be like a 2m tall person apologizing for not being tall enough – you're already taller than most people, there's nothing to apologize for. ;)