Is it too late to try the NC Rule?

The love of my life broke up with my last month. She was always madly in love with me and we had everything and more in common. She claimed her feelings were being drained because of our situation and my inaction/complacency and that I never went the extra mile for her anymore. We didn’t go out places on our days off etc. She claimed we just aren’t right for each other and that it was over. She said she needed her time and space but told me we could text but no phone calls or seeing each other as it was too painful for her. After that, for the next 3 1/2 weeks (until earlier today) I broke every rule in the book (unfortunately I’d not come across this site). For a day or two I’d keep it civil, but then I’d bombard her with texts, begging, pleading, professing my undying love, saying that I would change etc. on and off like that. She said that it was pushing her away and that I didn’t respect her or her wishes…

That’s when I realized I had to stop. She’s already told me by this point that she thinks we’re not right for each other and that it’s over and I know I’ve made it worse by breaking all the rules…She’s 19 and I’m 26 and we’ve been together for 2 1/2 years. Do you think that despite my constant begging and pleading, that the NC rule will still be a viable option? And what if by that time she really is seeing someone else? Or simply has interest in someone else despite what the article said? Do I just continue NC until she’s single?