preschool help 😩

Im a mom of two girls a soon to be 3 year old and a 7 month old. Im a SAHM btw so ive been with her every day of her life. My neighbor, one of her friends and me were all going to start our 3 year olds in preschool at the same school together this fall. From the beginning I was really upset and didn’t want to put my baby in school yet. They talked me into it eventually and I felt better shed be with friends and moms I knew were doing the same thing. I know she’ll probably love it but I just dont want to give her up yet if you know what I mean. Shell be in school for the rest of her life 😭. It makes me so sad. Now I was prepared and finally okay with it and all of the sudden the two other moms aren’t sending the kids there and trying something else. This just came up randomly and I was like wait what I thought they were going. I cant believe she wouldn’t of even told me if I didn’t say something. So now im all upset again to send her😭😭😭. I thought Id have the support from them and wed do it all together. When is the right age to send to preschool?? Should I wait until shes 4 or is that to late? Do I keep her home and hope shes not bored since she’s getting older? Uhhh whys this mom thing so hard 😭😭😭 please no rude comments. Im just a mess about sending my first to school it’s heartbreaking. Give me your opinions. TIA!!!