Late 30's and TTC... Scary!

Ami • Follower of Christ, married and pregnant with 4th baby!
Some of you know and have read... I am going to be 38 in October. Currently I have a 16, 5 and 2 1/2 year old boys. 
​We thought we were done but have recently started trying for another baby. It would be lovely to have a girl but will be happy regardless.
​I am nervous!! Just being honest.
​I am older. I am healthy but I have anxiety. 
​I think it's hitting me at the possibility that I could be pregnant really soon. 
​I am still nursing our 2 1/2 year old (not exclusively) and the thought of doing this all over is scary and exciting all at once.
​I am so crazy for our children and it brings me so much joy to be a mommy. I am nervous about the whole pregnancy part of it. 
​Anyway... Just wanted to put that out there... 
​Any other ladies about my age or older that share these feelings?