SI is something very personal. It doesn't have to and shouldn't be a burdon you carry alone. However, it is something that should, in my opinion, only be shared with those who need to know (family, T, Dr...) and those friends who have weathered some storms and proven their loyalty.
Let the friendships develop. If you have doubts or need to ask then it might not be time yet.
Most of my friends SI and most did not tell me until after we knew eachother at least a year. Sometimes I knew before they told me but respected it as it is their story to tell or not and only when they were ready.
If they are true friends it won't matter when you tell them. Now may not be the time to test things by sharing something so personal.