One year, not three.
no, firts in chapter 90 they said that 6 years pased since the day the colosal titan make his debut, and now in chapter 9 they said that 9 years passed since the day the send the armored and colosal titan so yes 3 more years passed sinces the chapter in the beach
It said it's been 9 years since the recapture plan started, but we don't actually know exactly when that was. You could assume it's when the first sent the colossal and armoured titans to knock down the wall (the beginning of the manga). If that is the case you would be right. However, we don't know for sure yet that is the case. Hopefully the next chapter will clarify things.
We had a 3 year time skip :O