Meeting ex at a party soon

Hi there. My ex broke up with me almost 3 weeks ago. We dated for almost 4 years, 2 1/2 of which were long distance but we saw each other during the holidays and about once a month during term-time. The breakup was amicable, I let it happen and was as respectful and dignified as I could be. She didn’t give me specific reasons for the break up, even when I asked, instead telling me ‘I love you but I am no longer in love with you’. However, upon reflection, I believe that the biggest contributors were my dependency on her to help me with my poor mental health, and the fact that I had let said mental health get out of hand to the point where I was no longer fun to be around. My aim is to learn to be happier alone, and I hope that this may open up the chance to try and reconnect in the future.

My issue is, we have both agreed to go to a mutual best friend’s birthday party in another city in a week’s time. We have agreed to meet there briefly before meeting the others, just to clear the air. However, I feel like the meet-up is coming at a difficult time as I have been unable to grieve properly due to exams, and I don’t want to say or do anything that may compromise my own healing, or my chance at reconciliation. I still love her, and believe that our relationship is worth saving provided we both put in work to better ourselves beforehand. I was wondering if anyone could advise me how best to go about this meeting and the subsequent party, as well as what I should focus on regarding trying to reignite the spark in the near future.

Also, I should mention that we have been no-contact since, with the exception of discussing this meetup.