Sounds like you're being too self aware. You're wanting to strike up a conversation, so go with whatever hits you. But don't lean on every nuance of reactions as if you're looking for those around you to grade what you say. Conversations have a life of their own so just go with the flow. The only time to check the temperature in the room is if the mood does not justify a conversation. Some people are not morning folks and others are. So know your company as best you can and join in if a conversation is in play. Be confident!