Thoughts on child care

So here’s a little bit of my back story, I have a son from a previous relationship, he is currently 9 years old and has been in the same daycare his entire life, since he was a year old. I now have an 18 month old daughter with my current boyfriend, we have been together 6 years and live together. My maternity leave is almost over and I’ll be going back to work in January. I had planned to put my daughter in the same daycare as my son, it is costly but it’s cheaper than most daycares in our city and they are amazing. Well my sister in law offered to watch our kids while we were at work, but she is young, only 21 and she has no childcare experience at all. She would also have to be at our house every day at 6:30am and if she’s ever sick then we are stuck for child care. Whereas if we were to use the daycare it would be way more reliable. My boyfriend says daycare is too expensive and he does not want her going. My family is pushing me to do what I feel is right and put her in daycare and his family is pushing for us to allow his sister to watch the kids. Ugh I’m feeling so stressed about this situation. What are y’all thoughts?