My heart rate is 98 bpm. Am I prone to arrhythmia or tachycardia?

Hello doctor,

I am a 23-year-old male. I have no symptoms and I am not taking any current medication. Three years ago I once went to the hospital because I felt my heart was beating really fast, and they did some EKG scans and a blood test on me saying that everything is normal. They also gave me the Holter monitor and when they checked the results they said this was normal. I do not smoke or drink alcohol maybe three times a year I will drink. I used to do some shisha but that has stopped for the past three years. Since then I have never been to a hospital for the health of my heart. However, since then, my heartbeat has just been higher than everyone else but I do not get headaches or any other symptoms. I used to stress a lot. However, things are going well now and it has cut down. I wake up at times during the night but fall back asleep very easily. I have done gym and dance classes for over a year and I feel fine when working out. I went to the GP just a week ago due to my girlfriend having some concerns. I asked them to do a regular check and they said my heartbeat at that moment was 98 and he said this was fine. However, my girlfriend gets really worried about this and feels that something will happen to me. She just needs some medical advice in order to get her the assurance. She has been checking online for some answers and it is said stuff like arrhythmia, tachycardia, etc. She also says that the normal is between 80-100 bpm and why is mine on the top end? Is it a serious cause? Or does heart and pulse rate vary? Also, I have been checking the prevalence of heart diseases, etc., online and it is very rare for someone at my age. What more should be done?