My mother has some ways I was eager to copy and others that I have tried consciously to avoid. Sometimes, I find myself thinking/feeling/acting in a way she did that I disliked. But then I try to catch myself and remember how that looked to me when I was a young daughter/wife/mother. As long as you're aware of what you don't want to do, I think you'll be ok.
I must admit, this worries me:
"I am an only child and have often longed for brothers and sisters, even more so now that I'm older. "
While I'm sorry you miss having siblings, I hope it doesn't mean you are already becoming emotionally needy. Or if so, that you'll find other ways of coping besides turning to your adult kids. Not that you can't reach out to them, sometimes. But I trust you have a network of friends, etc. to socialize w/ and hobbies and/or a likable job that keep you occupied and mentally stimulated, as well. I also hope you're aware of avenues to help in your area (home visitors/health aides or whatever you might need, later on), so that you don't necessarily have to lean on your sons/daughters, even if you become sickly in your old age (hope you don't, of course!).