Currently have a 9 year old - torn over whether to have a se

So, the title says it all.... I am in deep conflict about it.
I am 34, almost 35 years old. Whilst I dont have a deep yearning for another child - I am aware of the ticking clock and feel that if I dont have one now, then I wont have one ever. Mentally if I am one and done, I need to know that so I can focus on what we have, our future, and the benefits of being a family of three. I also have a garage full of baby stuff that I need sort out / sell!