That's good to know.
But you have only known me for a short while, so how do you know that it was there for many years?
So, are you saying it looks bad? :(
More lessons about normal conversation:
When you want to say something, unless it's something important, or the person who you are talking to is someone formal and elder like teachers, you don't need to tell them that you want to say something. Just get straight to the point.
And a more correct version of the second sentence would be, "You did not change your avatar for many years, so it is looking odd.". Also, in face to face conversation with people, try to use shortened words with apostrophes like 'didn't' for 'did not', or 'it's' for 'it is'. You already use 'I'm', which is just short for 'I am'.