Collins overcame fourth seed Elena Rybakina in just over two hours to become the sixth American woman to claim the crown in Miami.
"I have always wanted to win every tournament that I have signed up for, but I do think that because it is my last year, I really wanted to try to win a Masters 1000 this year," Collins told reporters after winning the third WTA title of her career.
"That's really important to me. That's something that I talked a lot about with everybody close to me. I really wanted to make a push to be able to bring out my best tennis.
"I'm so glad that I have been able to figure out some of the physical things I have needed to do to peak at the right time and to feel like I'm ready to go. I certainly did that this tournament, but it has been a goal. So I got to tick it off the list."
The former Australian Open runner-up announced in January she would be quitting the sport in 2024 and that she hoped to start a family.
Asked if she was reconsidering those plans, Collins said: "No, I'm not.
"I feel like all of these questions are coming from such a good place, because I feel like a lot of people would like to continue seeing me play well.
"But like I said, I have some health challenges, and with those health challenges, it makes things for me away from the court a little more difficult. I hope everyone can respect that. It's a very emotional and personal thing."
Collins, who is from Florida, thanked the home crowd for their vocal support throughout the match, saying: "It was just such a happy day for me on the court.
"Whether I won or lost, having the crowd support, I have never gotten to experience anything like it... It literally felt like I was playing in front of thousands of my best friends, I just - yeah, I'll never forget it."
