Ex Girlfriend Anxiety

So I'm in highschool and started dating my first boyfriend two months ago. He's really great but I can't help but feel intimidated by the fact he's had another girlfriend for over a year. He has way more experience than me! He's my first kiss too and I have no idea if I'm meeting his expectations. I can't help but worry that he compares me to his ex... What if I'm not as good of a kisser or even just a girlfriend as she was? Plus she broke with him, and I knew it was really devastating/unexpected. He seems to have no lingering feelings for her, but can you really stop loving someone? Does anyone have any tips/advice or personal experiences? Please share!