Tattoo for my twin who has passed

I am a 20 year old female looking for some ideas for a tattoo to honor my twin sisters life. 5 months ago I lost my twin sister in a terrible accident. She was leading a horse trail ride when a 70 ft.rotted tree fell on top of her, killing her instantly. The accident happened about a month after our 20th birthday. Of course like most twins, we had a special connection when we knew something was wrong with the other...even in different cities, states etc. My family did not find out about the accident or her death for about 5 hours because she was living in a different part of the state. When we found out the time of the accident I realized I had been feeling extremely depressed around that time of day. I told my mom that I felt an overwhelming need to be in a car crash or be hurt my some uncontrollable force. Something was not right and I even called my psychologist to make an appointment for the week ahead because I thought it was my anxiety. I do not doubt for a minute that my connection with my twin was trying to tell me something happened. I felt as though half of me was gone. So I really would like to get a tattoo in honor of her. I don't want her death date on me but I have tossed around the idea of putting our birthdate on me. I also have decided I either want it on my back below my left shoulder blade or on my ribs. I have thought of somehow incorporating an infinity symbol or some other way in symbolizing that we will be twins forever. I also tossed around an idea of getting the last three lines of the prayer of st. francis of assissi, which was her confirmation saint. The lines read: "For it is in giving that we receive, in pardoning that we are pardoned and it is in dying that we are born to eternal life." I do not want all of these elements in the tattoo but I would like outsiders opinions on the ideas and what would look nice. I also do not want it too large but I am not afraid to go slightly bigger.

I am sorry for the loss.I have no answer for you and the pain you have.Here is what i consult with my clients on memorial Tattoo's. What was the one thing that drove them? what made them stay alive? what was there most favorite thing in life? what was there favorite color? think about some of these and incorporate a nice custom piece.There favorite animal? and so on. hope this helps. again the loss is hard,and my sympathy and condolences to you.wish you best on your venture.Don