I'm not lawyer, and especially not a Thai lawyer, but no, I don't think it works that way (guilty farang until you can prove yourself innocent.)
Thailand is not an 'adversarial' legal system, so they are not so interested in determining who was right and who was wrong so much as they are interested in knowing the facts of the incident and making all parties whole.
Thai traffic laws are not easy laws with which to assign 'blame. A motorcycle with no headlight at night, or a motorcycle passing on the left shoulder, or driving between cars in adjacent lanes might be considered illegal in the West, and any resulting accident would be the fault of the motorcycle in the West. In Thailand, this is the 'traditional' way they drive and it is up to the car drivers to be on the lookout (yes, the police might pull over a motorcycle and fine them for no headlights, but in an accident, that might be as useful to you as trying to claim it's their fault because they weren't wearing a helmet .. yeah, illegal in the eyes of the police, but not so interesting in determining the process to follow in an accident.
So, from my experience what they seem to do is go with determining the facts so that anyone that broke any laws will get fined (not sure if they fined you, but if they did then there will probably be some piece of paper telling you what you did wrong ... and likewise the girl on the motorcycle will no doubt receive a fine for having no insurance and no helmet.)
The insurance company will in this case pay for the damages (to your car at least, and likely the girl and the bike.) For incidental damage (phones, helmets, cloths, etc) It is up to you, the girl, and possibly the police as being the final arbitrator if there is a dispute, to determine how much each party owes the other (ie. since it sounds like she hit you, then that's probably not an issue, if say her phone got busted then you will not likely have to take any responsibility ... if on the other hand they found that you were at fault, then she could ask you to pay for her broken phone and the police would likely side with her.)
Again, this is my experience being in 2 accidents in Thailand, one with my Thai wife driving and a girl driving with no headlights at night hit us as we were pulling out of a parking lot (no headlight was not an issue, we were at fault, so we paid a small fine to the police, the insurance covered all damages and we sat down with the girl and offered to pay for her broken phone. Once we came to the agreement, the police noted what we decided for the records, and that was that.)
The next one was with me (Farang) driving and as I was turning right a car stopped to let me turn, but a motorcycle passed on the left (they drove up on the sidewalk to go by) and clipped my front bumper ... we both had insurance and were both found to be at fault. I paid a small fine (500B) and insurance took care of the damages.
Once again, I am not a lawyer, but be aware that you need to forget all the 'legal fault' stuff you may have learned in the West ... it usually doesn't work the same way here, and it's not a case of 'you're farang, so you're automatically at fault, it's a matter of driving not working under the same set of rules and concepts, so these difference concepts will most certainly feel strange to us Westerners when we first run into them.)
One rule of thumb though is in most cases, the priority of who is in the right goes something like: motorcycles are always in the right no matter how stupid they drive, then comes cars and trucks, then dogs & cats, then bicycles, and finally pedestrians (although birds, snakes and big lizards might still have priority over pedestrians ;-) ) --- just kidding, I have no idea who has the right of way except motorcycles are a Thai's best friend so stay away from them and assume you will be in the wrong in any encounter, and pedestrians are expected to know how dodge traffic like an NFL running back!!