Not bad at all. My dog is a rescue and he is one of the greatest things that happened to our family. All situations are different. Just so long as you learn from this.

If you can't care for her anymore then it's a good choice. Give her to a rescue as rehoming is their job and they know how to make sure she goes to a good home and will make sure she gets desexed and microchipped etc if not already.

If you're getting rid of her because she is too naughty or not cute anymore then you're bad but good you're giving her the chance to be with a loving family.

Please don't be one of those people that gets rid of their dog then goes and looks for a new puppy straight away.

It really depends on why

If you can't care for it then re home it. I don't know the circumstances behind it but if it's in the dogs best interest then go for it.

If you're unable to give a pet the care and attention it needs, and rehome it responsibility, I think it's fine.
It's probably more irresponsible to keep an animal that you can't give the life it deserves.