First time to Europe

Wow, congratulations on your first time to Europe.

I think this is a very doable itinerary, but I have one suggestion. Ghent and Bruges are just a short train ride away from each other. I would stay four nights in one and do a day trip to the other. I'd recommend staying in Ghent, because from Paris to Ghent and from Ghent to Amsterdam are both shorter train rides (assuming you're traveling by train).

You might also consider cutting the Belgium cities, which are significantly smaller than London, Paris, and Amsterdam, to a total of three nights, and add one night to any of the other three cities. But some of this depends on what your interests are (museums? neighborhoods? food? nature?).

It's surely going to be a great trip, and October should be great weather for you to really enjoy it.

Lane's advice and comments are spot on. If you haven't been to Europe before, don't underestimate the time it takes to get oriented in each new place. . . new coins and currency, use buses and metros, find street signs (!), avoid getting lost in the maze of streets, signage in foreign languages to name a few.

For someone who's traveled in foreign countries your itinerary is doable, preferably with Lane's changes, but not slow-paced. For first-timers, it sounds very rushed. London and Paris are huge cities with sights that are spread out. Amsterdam feels somewhat more compact and less hectic than the other "biggies" but that doesn't mean there's not a lot to see and do.

As already suggested, Gent and Bruges are very close so not worth dragging luggage between hotels. Pick one hotel for both places, Gent might make the journey to Amsterdam easier..

London and Paris need a plan before you get there. Make sure you understand distances within each city. Your idea is viable assuming you don't waste a lot of time travelling back and forth - or standing around trying to decide where to go. As a starter this is the London Undergound network, try to keep within Zone 1, don't go beyond Zone 2 unless you have a family history reason - there is enough within those zones to fill a month https://content.tfl.gov.uk/standard-tube-map.pdf the map is schematic not scaled, go outside Zone 2 and distances expand.

Good, plan, most first timers in Europe only go to big cities. We have found that smaller towns and cities are wonderful and not to be ignored.

I actually think it's a nice pace. You've avoided the mistake 99% of travelers make; bloated itineraries with too many hotel changes. You can do a couple day trips (train/metro) from London or Paris if you want to mix in some variety, but there's plenty to see in those cities to fill your time. Ghent and Brugges are close and I guess it makes sense to do one as day trip from the other but they also make for a pretty easy transfer so I might violate my core tendency to avoid hotel switches.

Your dates are fast approaching and some attractions are timed tickets. If you are locked out of a must-see, you can always check some of the various tour consolidators like Viator who gobble up tickets and repackage them as tours. But don't think you have to do everything on this trip. Plan to come back.

Pack light. I can't stress this enough. Pick a color capsule so you can mix & match. Choose fabrics that pack down and don't need ironing. Splurge by having an innkeeper or laundromat do the work while you are enjoying your trip.

Choose small independent hotels. Avoid rentals that gobble up housing stock and ruin the flavor of neighborhoods.

There's a lot of walking, so get your steps in now.

Mix in a "chill day" around day 9 or 10. No plans, just sleep in, go chill at a coffee spot and watch the world go by, journal, decompress and soak up the vibe.

Public transit in Western Europe is great. Dive in on day one and use it during your stay.