Would you forgive your best friend if you find out she's been lying to you for the past months?

ok so i went to my best friend house to talk and chill and i wa rollerskating with her and she told me to carry her phone for i did while she was giving it to me a message pop up it was you where you can write the note and she wrote stuff about how she love my crushes and how she want to kiss and she thought i was stupid for being happy when i see him and stuff she look so guilty when i aks her to let me see the note she said he big sister wrote her big sis is 21 wh would she write that on her phone even if too Just make fun of her i told her if she like the same guy as me she can tell me i won't get mad she's been lying to me for the past month i Just don't see why she couldn't tell me the truth would you forgive her for lying to you ? or do u really think he big sis wrote it to make fun of her ?