Hi friend, please reread and note the caveat, “one of the very first”, which position number 5 certainly includes.
Also, a bit childish to want to rank systems based on creation date. If you feel like “losing”, please read on:
NYC total system length is about 800 miles (1.1km)
yearly ridership: 1.8bn rides
If we count the el’s (elevated rapid transit, which is still running), first ride was in iirc 1868.
But look, the important thing is that both our countries (presuming you live in the UK) have nice mass transit systems to keep cars off the roads. I look forward to visiting your country and riding its underground system at some point.