Funny, I went from 0 to 100 miles in about 3 months 4 years ago and I think my progress to 50 was pretty much like you described yours. I didn't consciously set out to do that, I just found I was comfortable adding on more and more to my ride. My basic MO was to pick somewhere I wanted to stop at exactly half of the distance I wanted to ride that day, go there, get off the bike for a bit, then head back. Doing that, I got to do several 150 mile round trips last summer. Right now, I don't really want to stop anywhere due to COVID so I've found that 100 miles is about all I want to do without stopping. Anything beyond that starts to feel tedious. I tend to eat a little something every 40 miles or so right now, my typical pattern preCOVID was to take a lunch break and have a full meal. Everybody is different on food, so you have to figure out what works for you.
My basic rule is that if you keep it fun, you can do a lot more than if you turn everything into some sort of "test".
A few basic rules for distance riding--be really careful to check the weather forecast before you leave, and pay attention to the wind direction and speed. Riding the last half of your ride into a strong headwind is awful, especially if you're climbing hills.
Plan your water--if you're like me, it's a while into the ride before I really want to drink a lot. Running out with 20 miles to ride can be torture. I usually plan on buying some water from a convenience store on a hot day, so that means bringing a lock.
Be sure to be equipped to fix a flat on the roadside.
Phones are actually safety devices.
Getting lost on a bike is a bit of a nightmare, be sure you have reliable GPS or know your route well.
My own personal basic rule--this is not a race, if I want to get off the bike to take a picture of a turtle, I get ff the bike to tke a picture of the damn turtle.
Oh, and a hearty CONGRATULATIONS! Thanks for letting us in on the celebration.