Im uncomfortable giving my 5 month old solids

I’m a ftm and my baby girl just turned five months. I want to do baby led weaning but I just feel so confused. Pediatrician saw my baby for like two seconds and just told me to try rice cereal and sent me on my way. I’m so lost. Even though my daughter is five months old, she struggles to hold herself straight when I put her in a high chair. She keeps her head up straight but she just tilts from side to side or folds in half. I feel like I need advice or maybe some reassurance. Is it okay if I wait until I’m more comfortable? Does she have to eat in a high chair?