Should I continue with this relationship even though I told her I would love to take her shoping?

I met a very pretty girl 20 yrs younger than me. I gave her my number and was so infatuated with her I told her I would take her shopping. She called the next day and asked for money for her meds. I gave her enough for that. She thanked me and even kissed me. She called the next day and asked me to take her shopping and she said her sister was coming. she bought a coat and then went off with her sister for the weekend. should I give her a chance because I can not stop thinking of her?