Blazor component: change classes based on number of children

I think it should be relatively simple but I could not find how to do it.

I have this:

<div class="row">
    <div class="col-6 col-12-small">
        <p>
            Lorem lipsum.
        </p>
    </div>
    <div class="col-6 col-12-small">
        <span class="image fit">
            <img src="images/test.jpg"/>
        </span>
    </div>
</div>

and I would like to create a component that would help make coding faster and cleaner. I would like something like this:

<MyGrid>
    <MyGridColumn>
        <p>
            Lorem lipsum.
        </p>
    </MyGridColumn>
    <MyGridColumn>
        <span class="image fit">
            <img src="images/test.jpg"/>
        </span>
    </MyGridColumn>
</MyGrid>

The component would change the classes depending on the number of GridColumn. If 2 children: "col-6 col-12-small", if three, "col-4 col-12-small",... and add maybe later more complexity.

Use a registration process with the parent component. This is a basic example the registration process could exchange a lot more information, parameters, sizes etc.

Parent.razor

<div>I have @Count children</div>
<CascadingValue Value="this">
    @ChildContent
</CascadingValue>

@code {
    private List<ComponentBase> children = new();

    [Parameter, EditorRequired]
    public RenderFragment ChildContent { get; set; } = default!;

    internal int Count => children.Count;
    internal void Register(ComponentBase componentBase)
    {
        children.Add(componentBase);
        StateHasChanged();
    }
}

Child.razor

@ChildContent/@Parent.Count
@code {
    [CascadingParameter]
    public Parent Parent { get; set; } = default!;

    [Parameter, EditorRequired]
    public RenderFragment ChildContent { get; set; } = default!;

    protected override void OnInitialized()
    {
        if (Parent is null) throw new SpitTheDummyException();

        Parent.Register(this);
    }

    public class SpitTheDummyException() :
        Exception("I need a parent! Place the Child within a Parent"); // C# 12
}

Usage

<Parent>
    <Child>One</Child>
    <Child>Two</Child>
    <Child>Three</Child>
</Parent>

Output