Hi OP,
I'm 37 as well and currently 13weeks pregnant with my first, and I have also been panicking about being too old, and whether I am doing the right thing choosing to bring a child into the world at this point.
Pregnancy was planned, but was a massive 180 as previously never planned on having children.
I am genuinely terrified that I will not be able to adjust from having ultimately a very self-centric life where I could do whatever I wanted to, to putting someone else ahead of everything. I am hoping that this is a normal feeling that mothers go through, and shows that we are realistic of the job at hand.
Not going to lie, the last 8 weeks or so have been tough, I have felt tired and sick all the time, and for the first time in my life I have felt 'old'. Everyone assures me that I will be fine when the baby is here, and that many many women have children at our age.
I have just started to tell a few people including my boss at work who was genuinely very happy and excited for me. The mid wife was great and made nothing of my age at all. Please don't worry about other people's reactions - those worth caring about will only want to see you happy.
I guess I am trying to say, I can really relate to everything you say, and I have spent the first trimester plagued by all the negative thoughts and worries, but tomorrow is my '12 week' scan and I am finally allowing myself to be excited. I am starting to think of all of the positives ahead, and less on whether I will ever sleep again.
For now i'm putting my faith in my body to know what to do, and the possibility of childcare when I need a break.
sending you hugs and support.