Ihearboost, mash it in D from a full stop and see what the speedo and tach read just before the first shift. 1st redlines (governorlines?) at about 40mph. FWIW, 25mph reads 3200rpm on the tach in 1st and 2100rpm in 2nd, in case you want to check without revving so high.

[edit] I looked at the first video again. Sure looks like it's close to 40mph before first shift at 4800rpm but I don't know that that proves you started from the right turn in 1st. I assume the shift lever was in D from the right turn.

Sixto
87 300D