My cousin lied to me, can I trust her again?

My friends smoke weed and cigs, and I dont. Ive never had a cig before even though sometimes some of them try to get me to try them, but its not for me. And weed ive tried but I really dont like how uncomfortable i feel and unrelaxed i get for some reason when everone else seems pretty relaxed lol. im 22 and my cousin is 21. Were very close like sisters and she knows how i feel about weed and cigs. The night before easter I went to a metal show with my friends and then spent the night at my ex boyfriends( who has 4 roommates who all smoke weed and cigs while he does not) So my hair and clothes always smelled after being there. So i went home easter morning to my moms where my cousin was & we were going to carpool out of town to our familys for the holiday. I hugged my cousin and told her i smelled and had to get into the shower. Well she told her mom( my moms twin so theyre really close) that I reeked like weed and cigs..my aunt(her mom) has the biggest mouth ever and is very irrational. Aunt called my mom a week later concered i was smoking weed and doing drugs. My mom knows i dont so wasnt concerend and told me my aunt called. I immediately texted my cousin calling her out asking why she told my aunt this if my cousin knew Im not like that...like what was the point..my cousin called her mom from colleg all mad for telling my mom my cousin told her these things, I know my cousin called my aunt about my text cause my aunt then called me explaining herself telling me my cousin told her in all confidence...while my cousin proceeded to lie over text, not knowing my aunt had called me, my cousin said 'i NEVER said anything of the sort about weed or cigs' On the phone my aunt was telling me her daughter(my cousin) is so lucky to not have crossed paths with drugs. When really she has. So I look like the bad guy while my cousin looks like the perfect angel that shes not. SO...now that i know my cousin is two-faced...i dont really care to be close to her anymore, it actually gives me motivation to make my life better than hers in the future to rub it in my aunts face.