Aw all your feelings are completely valid! Your baby is growing up and finding her feet, It is hard not to be anxious in this situation but the great thing is she is going with a friend and I am sure they will keep each other safe. Just let her know you are feeling this way and ask if she wouldn't mind updating you throughout the night to ensure she is okay! I am sure she would be happy to do so I can imagine she can understand how you are feeling at the moment.