Developing feelings for my late fiancees cousin

Don't feel like I can talk about this easily with my friends and family so hear I am talking to strangers online about it! Just under 5 years ago I lost my fiancée to suicide, she was suffering with psychosis and it finally got the better of her. After a long road which has included my own mental breakdown, suicide attempt and continued recovery from the former I have reached a point where I have started dating again and am open to and somewhat looking for a new relationship. The problem I am currently facing is that recently I think I am starting to develop feelings for my fiancées cousin. No one else from my late fiancées family lives locally to me, her cousin however moved to the same city as us for university and stayed after she graduated. She was very close to my fiancée and their relationship became one more like sisters then cousins, her cousin had become part of my social circle and still is and has continued to be very supportive of me. About a month or so ago she told me she was thinking of breaking up with her then partner as the relationship had no future, it was around this point that I started to realize I was looking at her differently. I've always thought she was an amazing person but I still somewhat viewed her as family, we always used to refer to each other as cousin in laws even after my fiancées death. She told me the other weekend that she had now broken up with her boyfriend since then I can't stop thinking about her, but at the same time I feel incredibly guilty because of her being related to my fiancée. I am terrified of upsetting her or freaking her out, let alone what both families would say. I'm not even sure if it's just me being incredibly lonely and noticing the single people in my life. Do I talk to her about it or do I just try and push it down and forget about it? Help!

She hasn't said or done anything obvious that makes me think she has mutual feelings. She's always there for me when I'm struggling with my own mental health or anything else in life and we always seem to enjoy each others company. But then again we do have a shared experience from my fiancée and just know each other very well and genuinely care about each other. We were always close and good friends going back to when my fiancée was still alive. Don't know what to do should I tell her about these feelings or just try and bottle them up and avoid her for a while and hope they go away. Am I a bad person for having these feelings I can't help feeling really guilty about having them while my fiancée is gone.