well use

4-4-2
or

4-3-3

or even

3-4-3
References :
well……………………………… my brain

well i sincerely hope you had the opportunity to have coached this young players for a time that will give you an idea obout the capabilities of each player on this suposedly team you are asking for help
however this phylosophy remain that the coach does not actually detemine fiormations, but the players detemine team system/ formation. what the coach have influence on is the stratgies and pattern of play.
so if we agree on that, then the way forward should be clear now.
as the coach you should konw your players, their abilities in different areas of team blocks both offensive and defensive. although in some areas particular qualities are appreciated, such as the in the central defense where tall players are often prefered as to short players. on the wings most prefer fast and flexible players with courage and confidence to take on one to one to creat space for themselves for a cross.
Ball mastery will be vital consideration for choosing midfielders for your team, such players will require vision and distribution abilities, they must be willing than most on the team to help in all game situations. they provide core elements of the game tactics and skills executions. although they may differ in duties, one may be assisge the defensive duty and the other may be the offensive duty, but modern football transend all that notion, modern football require all players to be functional in almost all team blocks
Your strikers should be choosing carefully, tall and agile players often are prefer some how due to their over all quality which includes areaial efficiency and range of reach in battle for a ball. should you prefer a shadow striker, you should be looking for a grate technical player who has the ability to link up play
i believe , although you are dealing with younger players you should still be in a position to notice these qualities in them.
Although there are several differen6t formations, but the very foundation of individual abilities is build players on a 4:4:2 formation. with kids we all know that they are often attracted by the position of the ball, so your position is to constantly remind them of their responsibilities. one would say they have a short concentration span

well in conclusion, i would advice you to measure in these qualities as the yard stick to deciding what formation you should use

i wise you good luck

Manneh