@OP, it is normal for the price of Bitcoin to fluctuate. As we know it is still considered as highly volatile asset. So don't worry if your stash is in negative at this moment. We are still in a recovery phase, just wait a year or two and you will see a massive increase of your profit once Bitcoin rallies toward its new all-time high after this coming halving event.
I have two great concerns about Op
1. Why do you have to sell your property to invest in bitcoin?
Don't you have any other need for the bicycle? Investment is done out of what you earn and not by selling properties, unless is the property you have no need of anymore.
Well it is better to sell your bicycle than let it get old and become useless. As you see bicycle value decrease as it gets older, selling it for a possible asset to double or triple in a couple of years is way smarter than having the bicycle and waiting for it to become worthless.
2. Why almost every newbies first bitcoin investment is always on CEX, especially Binance? Can this trend everly change to the right thing?
Binance is a popular exchange and possibly their mentor advice them to buy their first Bitcoin on Binance exchange.