To have a 2nd kid or not to

I never thought I would have so much "mom guilt" over this. I had a daughter back in december. Shes the best thing to ever happen to me. That being said, I was born a twin, so I litterly have NEVER been an only child. Not even in the womb. I have no idea what it's like to be an only child. However I feel like one baby is enough for me. And I used to think that once she was potty trained, maybe we could have another. But I just dont know about that now. See I've always wanted to be a young mom, I'm 23 now. And im currently covered under my parents (and step parents) family plans until im 26 (yay insurance) after that, I'm only covered under my husband. So having a baby would be like 3x more expensive. And I want to give my daughter the world. I dont want to have to decide what sports each kid can play or worry about kids feeling left out at christmas or constant fighting (cuz siblings are not always great friends) just weighing the pros and cons stresses me out. Cuz if I were to have another baby, I'd want them close in age so they would have things in common... but I dont know if I want to raise a toddler and a newborn at the same time either.... and I hear 2 under 2 is a nightmare... but my mom was an only child and she talks about how she would get a board game as a birthday gift. But then never get to play it. Now I would play with my daughter so she wouldent be lonely.

How did you decide to have another baby or not to?