Not able to express love to partner

I am a 18 year old boy. I used to like a girl in my tutions. We chatted on fb nd then we started talking on texts and finally we are in a relation now:-) Its like a dream come true. She is like super hot and to be honest i m the reacher. It has been one month and we met 4 times went on long drives and shared happy spl moments. We even made out couple of times and she always said i love you. Now suddenly she started behaving wierd. Like one day we had a fight and i asked are you not enjoying our relation and she said its a 50-50 feeling:-( Now i think the problem is my talks. I m also good looking and rich but since this is my first romantic relation i am not able to express and make her feel speacial. I just dont know how to be romantic please help. We dont even talk on phone. I feel nervous nd never call her. Help me. We havent broken up please advise how to make her fully mine because i m damn sirious.