This is so exciting ! I went to the top of jungfrau on my euro trip with Contiki!
That's quite a trip, but I doubt that you actually got to the top of the Jungfrau. Where I bet you did go (and I went several decades ago) was to the Jungfraujoch, which is the top of the rail line past the top end of the Ice Palace. Here is a description of the trip to get there:
The Jungfrau railway climbs from Kleine Scheidigg to the Eiger Glacier station, well known for its mountain restaurant and polar dog kennels, then continues through the Eiger tunnel, only stopping to enjoy spectacular vistas on the way to the highest railway station in Europe. The Jungfraujoch is 3454 m up.
The mountain restaurant with its beautiful panorama terrace is located below the Eigergletscher (Eiger Glacier) at the foot of the majestic Mönch and Jungfrau massif at 2322 metres.
The actual Jungfrau is 4158 m and you have to walk through a treacherous ice field plus climb to get there. I doubt that you actually did that. Only experienced climbers should attempt it and tourist groups certainly do not. I didn't. The height at 3454 m made me very ill and I had to get down as rapidly as I could.