I'm so sorry to hear about your loss. Anniversaries of such events are always the hardest times. It's good, though, to take some time to think about and remember your mum. Four years probably feels like half a lifetime, but at the same time like the blink of an eye. Time is funny like that. However, the one thing about time is that is truly is the greatest healer and what is still painful now, will slowly get easier.
Yes, I'm fine. Thank you for asking. I lost my mum too, but that was 18 years ago, so I don't grieve as much as I did. Like you, I regret the most when she misses something important in my life, like the birth of my children and watching them grow up. I can assure you though, that although you never forget them and never stop regretting their loss, time does heal and our own lives do continue. I'm sure your mum, wherever she is, is very proud of you and your children.