Old ticket backlog evolution over time

Hi,

I have been trying to plot the evolution of old ticket backlog in a chart (i.e. I want to be able to see how many tickets older than X days were open every day, in the past 2 years), and so far I have been able to plot the evolution of all backlog (regardless of its age) in a chart (with DimDate[FullDate] in the X axis) with the following measure:

BacklogOverTime = 
IF ( MAX ( 'DimDate'[FullDate]) <= MAX(FactCases[CreatedDate] ),
COUNTROWS (
    FILTER (
        FactCases,
        FactCases[CreatedDate] <= MAX('DimDate'[FullDate])  &&
            ( FactCases[ClosedDate] > MAX('DimDate'[FullDate]) || ISBLANK( FactCases[ClosedDate]))
        )
)
)

I tried to add another AND condition into the COUNTROWS filter formula like the following (I was trying to only capture tickets older than 120 days), but I am not getting any result when I add it:

DATEDIFF(MAX('DimDate'[FullDate]),FactCases[CreatedDate],DAY)>120

Appreciate any help if anyone is familiar with these types of calculations.

Thanks.