Richie,

I feel the existence of entities. Others will have their own words for these entities. I struggled for a long time with the terminology while trying to explain spiritual things.

Let me try to explain -

None of us are new, the body is new but what we seekers are dealing with within and struggling to understand, is not new.

Most people are happy to live their lives on auto-pilot. Then there are those of us who had something happen to us that awoke something in us causing us to become aware of more than ourselves. Perhaps we had a tough childhood or were in some kind of an accident that caused that part of us to awaken.

Lets get back to your siblings.

This may seem quite fanciful but -

Your mum may not have been strong enough to carry all three. Or the entities preparing to enter the new bodies may have known what hard work even what hardship it might have been for your parents to bring up three children. Perhaps the entities in their Godly wisdom knew that it would be best for all concerned to allow only one new body to proceed. Perhaps yours was the youngest entity, the one that would benefit the most from living and learning in this life time.

Just a few thoughts.