Plant is tall yet pot is disintegrated
It won't be a problem if you proceed, carefully, unless it is a type of plant that cannot handle disturbing the roots.
https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm
I have been feeding my house plants with miracle grow do I need to fertilize plants too
Your Miracle Grow applications are fertilizer so that is all you need to do. Here are lots of tips for growing houseplants with links to more articles.
https://www.gardeningknowhow.com/houseplants/hpgen/beginners-guide-to-houseplants.htm
https://www.gardeningknowhow.com/houseplants/hpgen/mistakes-people-make-with-houseplants.htm
This plant has been my pride and joy for many years. BUT, I think we're to the place where I might need to divide her. Her name is Fernie and she is between 45 and 50 years old. I have divided her before, but I think I may have waited too long this time as she is VERY heavy even when the soil is dry. Have you any suggestions on how I might pare her down in size a bit. See pics below (neither are great, but you'll definitely get the idea).
We didn't get any photos or the type of plant, but these articles should help:
https://www.gardeningknowhow.com/ornamental/foliage/ferns/how-to-divide-fern-plants.htm
https://www.gardeningknowhow.com/garden-how-to/propagation/propgen/dividing-plants.htm
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/splitting-succulent-plants.htm
https://www.gardeningknowhow.com/houseplants/jade-plant/separating-jade-plants.htm
Spider plant , lily, succulents, cactus, possibly elephant ears as well.
These articles will help you with repotting:
https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm
https://www.gardeningknowhow.com/garden-how-to/info/repotting-beginners-guide.htm