You've had a huge shift in priorities over recent years - as we all do when having children and expecially when you're raising them alone.
Firstly, don't feel guilty for still going out when they were younger. That was what you needed at the time. They were fine. It's OK. It was probably better for them that you transitioned smoothly to where you are now rather than just losing a part of yourself overnight because you were able to find yourself as a mother at your own pace and in your own time rather than having your old self ripped away from you and being forced to accept, "This is just how it is now." I'm assuming single motherhood wasn't (strictly) your choice at that age and that is hard.
Secondly, you're not boring or being boring. Who decides that? If you are happy with the life you live then who ould it be boring to? Other people? They don't matter.
However, thirdly, I agree with those who caution against letting your children become your whole world.
Im 52. I've been a single parent twice and for most of the 27 years I've been a parent (my youngest is still at university) so I have some experience of this.
Once my children were a little older (still at primary school though), i started to think more about myself again. I took up hobbies, met people, made friends. I saw women around me who'd been wonderful parents but who had neglected themselves and they found it a lot harder to adapt when their childen became.more independent and had their own lives. I found that transition a lot easier because I had invested in myself as well as them.
You may have lost interest in going out and getting 'mortal' but you are still allowed to have adult fun when you are ready to do so again. As for dating, that only becomes an issue when you want to do it. Until then, it's not important.
ETA: by adult fun, i dont mean getting pissed! I just mean enjoying things as an adult rather than centering children and children's activities in everything you do.