Best Of

This is the exact reason that FamilySearch has now instituted Family Group Trees - they allow living family members to see other living family member's records and their connections to those who have passed on.
Chose the family member who has the most living records added (once again only they will be able to see them at this point.) This may be your Grandma!
Have that person start a Family Group and copy all their living people into the group.
This becomes a Family Group Tree.
Now your Grandma (whoever is the Family Group owner) invites you and all your living relatives to be members of the Family Group.
Suddenly you all have access to the living records!
You can use this space to share memories among living people and to coordinate your Temple work with the family.
There are several great articles here in the help section on creating and using Family Groups and Family Group Trees.
Enjoy.

@Bill Kaczmarek

I just noticed that when adding a relationship type there is an option to add a date. I wonder if a date has been added in the example you reference? If so, I would agree that this is the event date that should show on the Time Line.

After writing the above, I decided to test this out myself and was disappointed to find the fact that a child is marked in a step relationship and that the relationship did not begin until twenty years after the child's birth made no difference at all.

In my example, in spite of marking a "child" born in 1930 as "Step" (instead of "Biological") and that that relationship didn't occur until 1950, the 1930 event for the birth of a "child" still remained on the Time Line, instead of an expected placing in 1950 for having a "stepchild".

I would agree the Time Line is currently presenting a totally misleading picture and that the issue needs to be addressed in order to present an accurate recording of the facts.

As it stands now, the Timeline lists births of children when they happen. This is so with StepChildren too, listed as "children". And when a future marriage will later make a person a step-child, they are still listed on Timeline as Birth of a "son" or "daughter" , even though Step-son or Step-daughter would be accurate. Or more accurate yet, would be Future Step-Son or Future Step-Daughter.

Here's an example:

I was just corresponding with a relative in Poland who pointed to something that might be improved.  Have a look at https://www.familysearch.org/en/tree/person/timeline/G4DF-9V7 which is the timeline for Mikolaj Kador.   

It shows "birth of a daughter", which is confusing, for Marianna Wroblewski.  

Marianna is born at that time, that's true, but she is a future step-daughter, rather than a daughter.   "step-daughter" is less confusing.  "future" may be too much to ask for ;-)