I must have misread something. According to this discussion: https://tor.stackexchange.com/questions/423/what-are-good-explanations-for-r...
100KBytes is considered a fast relay. 100KBytes = 800Kbits = 0.8Mbits
Yes, you are right. According to the standards, 100KBytes/s or faster is enough for a relay, true. I did not find that explanation, to be honest.
I just had the comments from this blog post in mind: https://blog.torproject.org/blog/lifecycle-of-a-new-relay
The first comment and also the answer talks about exactly that. I would say if you can provide stable 100KB/s or more, or you want to be an exit node (then it's more important to have you listed anyway), you should provide a relay. Other than that, be a bridge, that's important to the network, too.
In your case, you should decide for yourself. Just do what you think is right.
Michael Armbruster