How can I tell if I love my 19-year-old girlfriend if I’ve never really understood what love is?

My girlfriend and I are both 19 years old and have been together for just over a year since we met in college. When we first started dating, I had a nice group of friends and life felt pretty normal. But once I met her, everything changed. The way we connected, the way we gazed into each other's eyes, and how we would linger on campus long after classes had ended just to be together were all special moments. We spent countless hours together, and for the most part, it was wonderful. I won’t pretend that I was perfect; I realize now that during arguments, I often prioritized my own feelings over hers. I noticed some changes in her demeanor and understood that I needed to adjust how I reacted to things. Over the last two or three weeks, she has been incredibly busy with work, and we haven’t had much time to talk. My mind started racing with thoughts, making me worry that she might be growing tired of me. This led to constant stomach pain and anxiety for a while. However, everything changed when she came over one day and reassured me while I cried in her arms. Now that I feel secure in her love, I find myself questioning my own feelings for her. I don’t understand why this is happening. I was devastated and anxious, thinking she might not love me, and that worry kept me from eating for days. But now, with that fear alleviated, I'm left wondering if I truly love her. It feels confusing, and I’m not sure if what I feel qualifies as love. She makes me happy—when I'm with her, I feel at home and relaxed. I adore her sparkling eyes and the way her touch feels. I’ve opened up to her completely, and it doesn’t bother me at all; I appreciate her vulnerability as well. She puts in so much effort for our relationship, and I genuinely can’t imagine my life without her. I've even turned to my faith, wanting to fight for our love and explore new possibilities together. But now I’m starting to fear that this might not be meant to be. I definitely don’t want to lead her on; I want her happiness above all. I’m happy with her, but I also can’t stop thinking about our future together, which I envision positively. Honestly, I think it might just be my overthinking—this is my first real relationship. She has met my family, who adore her, and I’ve met hers, who love me in return. I really need advice on what to do. Please help!