At age 3 children, developmentally children are usually at the stage of 'playing alongside' each other. In a pre-school / early years setting, you would typically see children playing with same toys, but on their own rather than all involved in a large involved game together. 3 year olds may not be even interested in what older children will be doing. There is quite a difference in a child who has just turned 3, a child who is mid-3years and a child who isn't 3 until June.
In this situation your friends 3YO may have different play experiences to your not-yet 3 year old. Are there older sibling that they normally play with / go to pre-school etc / does the older 8 year old have a younger sibling to entertain or play with. It may just be that there was a different range of toys to play with and the 8yo loved to play with it, etc.
All sorts of things going on here.. don't worry about it with your not-yet 3 year old.
xx