If I text my girlfriend with my new mobile phone number, can she tell it's me?

At first, she certainly didn't know who scolded him (her), but if she is careful and you are careless, she will certainly be able to detect the clues in the process of your scolding, and then you will eventually be on her suspicious list through exclusion and suspicion. Finally, she can find the owner through the network operator. It's easy. She can pretend to pay the phone bill, give her phone number, and then ask the salesperson to confirm her name. So don't be opportunistic and naughty. Be nice to your girlfriend!