There are many excuses not to act on that idea of yours. You don’t have the equipment, you don’t have the fitness, you don’t have the finances and you need someone else to join you. It is only when you go do the thing that you notice you didn’t need all of the excuses or at least not in the amount that you expected.
Sometimes I waited for a perfect opportunity before going on a hiking trip for a few days. Eventually I decided to simply go and plan a trip in two weeks, regardless of who might join and what equipment I have available. By being so decisive and making your plans clear, it is more likely that others will join you on the trip. Even if they don’t, you now have an opportunity to spend some time alone and explore yourself this way.
That old backpack might hurt when the non-padded straps cut into your shoulders, but this is easily fixed by adding a towel or shirt in between. You might be surprised by your creativity when you forget your spoon. You’ll ask others for a spoon, improvise utensils with twigs or even completely forego cutlery and drink a soupy meal straight from the pan. You’ll find ways to make do with what you have, and often realise that you don’t need as many things as you thought. It’s a shame to miss out on the experience because of your excuses. The inconvenience or even pain will be forgotten, but the memories will stay.
It is better to go on that adventure and find improvements for next time, than optimally prepare for it and never actually go. You can still be realistic in your expectations and maybe shoot for a hike with 15 or 20 kilometres per day instead of a daily 30 kilometres one the first time and with unknown fitness. Next time you can increase your daily distance, or just stay at your current level if you’re having fun. There’s always a level you can start at, and you’re ready to start now.