That does sound like Nebido, yes.
As has already been said, if the dosage makes you uncomfortable or if you are that unsure, I would suggest voicing these concerns to your doctor! They need to know if you are unsure etc!
However, I'm on Nebido as well, same dosage, and I got my second shot six weeks after my first, and my third will be in August, 12 weeks/3 months after my second! So I'd say there's no reason to worry, really!
My doctor told me that's how they usually do it with Nebido: Keeping the first interval fairly short (6 weeks) in order to I guess you could say "kickstart" your second puberty & raise your T-Levels fast (because nebido is a long-term, slow-release kind of T), and after the second shot, you get your shots every 3 months/12 weeks which is the usual for Nebido.
They usually do a bloodtest at this point to check your T levels, and some people might need longer intervals like 14 weeks to have their T levels be in a normal male range, some need shorter like 10, but about 12 weeks works for most!
I also know a trans guy on Nebido & same dosage who's doctor had him take his second shot after 6 weeks, his third after 8 and his fourth after 12, and he's fine!
So... maybe speak to your doctor if you are really worried/anxious because of it, but if you're wondering if it's normal: yes it is!