The Erhu is an instrument that is hard to pick up. One of the bottlenecks when learning the Erhu is getting used to the posture of the right hand, which you hold the bow with.
Another is with the left hand. Unlike our western counterpart the violin, Erhu does not have a fret board. It will be more challenging for learners to find and remember the position of notes and how much force to use for every note to find the correct intonation. In exchange, we have a number of techniques that are unique to the Erhu which the violin is unable to perform.
Having said that, the Erhu is an extremely rewarding and satisfying instrument to learn. An instructor can definitely make your learning much more simple and enjoyable!