Moving in with my friend??

So my best friend is 25 weeks pregnant, she is currently living in her parents with her fiancé. But, they are now talking about getting a 4 bedroom house, and told me I could rent a room. The rent on the whole house would be $1550, and she told me for my bedroom it would be $550. I agreed, she’s now telling me the deposit will be $3200 including 1st months rent which is fine and told her I could pay double my rent so $1100 she’s now saying that it’s not enough. My name won’t even be on the lease so it’s not even technically my house. They will have 3/4 of the rooms and it’s technically there house. Am I low balling by agreeing to paid a 3rd of the deposit?