Problems in my relationship with my girlfriend

My girlfriend just broke up with me. Our relationship started out she came on to me and I asked her to be my girl because because when I first met her we chilled with each other every night and I really started liking her. So when she told me she doesn't want to be with me, anymore because I lie to her about simple things, I am afraid to truly express I how I feel, instead I just sugar coat it, and I dont make her feel appreciate, also I just live life and dont think before I do, which she said shows that I dont care.She thinks it's best if we part ways. At the moment I dont feel bad for losing her or maybe it hasn't hit me yet but I have learned so much being this is only my first "real" relationships and I am 21. Sad I geuss but what is wrong with me and what should i do to fix it?

Listen to your ex-girlfriend and learn, so you will not lose your next girlfriend too.