People accuse you of using AI because they confuse language proficiency with text polish. A clean, simple paragraph about your birthplace and daily life is completely realistic at A1-A2, even if it looks too neat to a skeptical stranger. Their assumption is their problem, not a valid measure of your Dutch.
Online language exchange platforms get a lot of low effort and sometimes fake posts, so users develop a habit of flagging anything that reads smoothly. They also have a stereotype of a beginner: short, mistake heavy, with unnatural phrasing. When they see a structured, correctly accented paragraph, their brain jumps to AI instead of updating the stereotype. None of that means your writing was flawless prose. It likely was standard, formulaic language, and that is exactly what an A1 learner can do after a week long intensive course.
The CEFR places self-introduction squarely in A1/A2. You can talk about where you live, where you were born, your job, and your hobbies. That is one of the first units in any Dutch course. You also had 30 hours of classroom time, which is enough to practice and drill the patterns until they become automatic. So writing a few correct sentences about yourself is not 'too good.' It is the textbook application of what you learned.
Keep a copy of your self-introduction and treat it as a baseline. Add one new clause each week, like a sentence with omdat or an opinion about your neighborhood. This shows growth and gives you something concrete to point to if questioned again.
If someone accuses you of using AI, respond briefly: 'Thanks, I've been practicing this exact text a lot.' Offer to switch to voice or video if they are interested. Those formats are far harder for AI to mimic, and they often dissolve the suspicion. If they keep insisting without cause, move on. You do not owe a stranger a full explanation of your learning history.
The bigger lesson is to learn to write the way you speak. In language exchange, people care about communication, not error free perfection. Include a small, personal detail that an AI would never invent, say something awkward or specific to your life. That makes your text recognizably human and also stretches your Dutch. And if you want more structured practice, a resource like Dutch Fluency can help you solidify grammar, but you do not need it to prove anything to anyone.