My and my girlfriend are falling apart HELP PLEASE!?

okay me and my girlfriend jennifer have been dating for 3 months on the 3rd on jan 08 will be our 4 month. okay we both think me and her are serperating apart. but i dont see how. were both shy and everything. we just started to kiss and cuddle like an month a go or some sh*t. and i really really reallly dont want my heartbroken if she breaks up with me. i had it happen already once and i dont want it to happen again. i really love this girl. and she thinks i still like one of my ex's a girl named myra, Just because she was my first kiss, how do i prove to her im a caring and a good boyfriend? and how do i prove to her i dont like my ex.? were going to the movie this friday together with some of our friends? what do you think i should do kiss her right i dont know hwo to kiss al that much i do but i dont you know. me and her have trouble making out(french kissing) hopefully will get better. and do i basically tell her i really love her with all my heart? what should i ger her 4 xmas?