Life is really strange i have violated ma principles

I did one silly thing today and still dont know what really came over me i bought some things for a girl called lilian who i don;t really know. I met her in a more mysterious way and just for some few days and i bought some things she asked me to buy for her but i realise one thing i did that was really right i told her i have violated my principles because of her just to tell her i will not do that for her next time i would have rather liked it if i have never met her why did this happen at all it might be for me to change her cos she does not know me but asked me to buy her something what if i wasn;t a human being i cld have caused her damage and she wld have regretted that act i have to find a way to tell her that she shd change that part of her