Traffic lane changed – accident – who’s right?

Hi, yesterday I had an accident. The road was 3-lane – left turn, right turn and straight track. I was in the left lane and the traffic light was red. Then I remembered that I had to go to the right, so to the straight track. I flashed and made a shoulder look. Then I saw that the lady to the right of me had some space free front. So I steered my nose there and hit a bit. Then I stood for a while so, b When she was then green, the cars drove in front of us all and I saw again whether she was giving me an advance drive. Since she then waited and did not drive, I assumed that she would let me through and decided to lift my hand as a thank you! (I always do that) When I was on the track, I had to steer straight, and at that moment she drove back right against my car. Afterwards we exchanged our data. We wanted to settle this between us and not call the police. But this morning she called me, and meant that I did 250€ damage. Her bumper and cot wings have been broken. I’m so stupid and didn’t get the idea to take pictures of the damage.What do you think? Am I completely guilty as a track changer or just a part since I flashed and made shoulder look? Plus I thanked you! I hope you can help me further. e Meryem