Name That Drama: Twists, twists, and more twists

Please help me find this drama I watched sometime ago which I love for the excellent writing. Basically, it is about a woman who was given a chance to go back in time to save a family member (her dad, I think) but in exchange, her physical body ages. Because it took her several attempts, she ended up looking like a grandmother in the present, making it very difficult to pursue her love and live like a normal young girl. I really love the ending of the series and would like to share the pleasant experience w/o spoilers so I badly need the title to share. Thanks in advance.