I'm an only child, and I have mixed feelings about it. I was a very happy child, and actually, I think being an only has made me much more outgoing and confident. I grew up abroad, and therefore I had to make friends, as we didn't even have any family living nearby. I was always being told to "go and ask that little girl what her name is", and my parents encouraged me to foster friendships myself, and never took it upon themselves to 'entertain' me, iyswim. We always took a friend on holiday, or I went with friends, and I can't remember ever being bored as a child, or lonely.
I think interestingly, it has been something I have thought about more as I have gotten older, and I would have always chosen to have a sibling, rather than not. I think now, as friends grow up and we all have our children, I would dearly love a siblilng to share all my experiences with, particularly when my mum is driving me mad!
I definitely like my own company, I can;t bear feeling crowded, and this adjustment was particularly deifficult whtrn dd was born, as I felt a bit suffocated initially.
I was very clear that I didn't want dd to be an only, and I am currently pg with dc2. I feel quite strange about it, tbh, as I have never experienced the sibling relationship myself, so somehow feel I am inflicting some terrible ordeal on dd by expecting her to share us!
I think my parents dealt with having an only child extremely well, and they have definitely made me the person I am today. Sometimes it is hard, all the focus is on me, and I am expected to be perfect at everything, perfect wife, perfect mother, perfect daughter. I would encourage you to ensure that you always give ds a sense of freedom and independence, and not one of obligaiton to yourselves.