Don worry brother!

But u need to take care of the following things

1. Yes ur gf was right it may pose a problem ahead

2. Its benign condition called Phimosis in which the foreskin of the penis still remains attached with the glans. There are various degress of Phimosis and ur seems to be of less severe type. Severe degrees of phimosis may cause problems with urination.

3. Do not try to forcibly pull ur foreskin back in an attempt to release it. It may cause another problem Paraphimosis which more dangerous.

4. But u can try with gentle traction. Really be gentle. But i think it will not work because ita natural thing to occur on its own

5. Why don u consult a primary care physician who can refer u to a surgeon if surgery is needed (hope u r in US). If u r in nepal u can straight away consult a surgeon

6. If surgery is needed u need to undergo Circumcision: its a minor operation. And infact circumcision is more healthy. And u will be fit within a week or so and u will enjoy with ur gf lot more and she too!!

6. If u r worried then go see a doctor!