Others options for my baby #2

How do you know when you are ready for baby #2. I love my son so much, he is my world. I feel a little guilty that I want another Baby. Does that mean I shouldn't be trying yet? I have not told any of my family that we have been trying for 4 months and my sister in law out of the blew tells me I am not ready for a baby. What what! How does she know want I am ready for and who does she think she is... then today my mother in law says "don't talk about babies she'll get ideas" like it's a bad idea. My son is will be 3 in two months is that too soon. There comments hurt and make me think I am making a bad decison.