My baby has a tendency to hit/scream at me. I'm worried if she goes into childcare at 18m, she will hit and get hit by her friends. How do I overcome this? And how do I ensure my baby doesn't cry too much in school as she's very timid?

I suggest discussing this with her class teachers and principal and find out what is the teachers and school's policy/approach when a students hit each other and what they would do when a child cries excessively. Would they carry the child away, timeout? (Hopefully not) etc.. Then you may consider following the same approach such that there's consistency in how you as parents and the school caregivers would react when she hits. I find that giving my child positive affirmations builds her confidence. Eg: "thank you for picking up your clothes, that's very responsible of you." Or "thank you for telling me that you need a milk instead of crying" or "thank you for putting your cup on the table, that was very helpful." My child was very timid and shy but she became very sociable and independent after going to cc.