To be or not to be?

Me and my boyfriend have been together for almost 3 years. We have a one year old son who is my world and so much more. Before I fell pregnant my boyfriend was serious about proposing to me on my 18th birthday. It came to the day and it was an amazing, I couldn't stop thinking about him giving me a ring but it never came. I wasn't upset or anything as I knew he probably wasn't ready but 2 of his brothers and 1 of his sisters got engaged and they have only been with there partners a few months. So I was a little hurt that still after having our baby and being together for almost 3 years he still hasn't popped the question. Am I over reacting or do I need to worry?