Now I will choose bitcoin
Its price is growing very fast and you can quickly increase capital, gold will not.
Bitcoin in the trend.
Bitcoin is interesting to me
Maybe, but in my opinion you shouldn't choose the asset that may quickly increase capital, because the bigger chance to get your money multiplayed means the bigger chance of losing whole your money or at least the part of them.
You should take care on the risk, and always choose the correct balance between risking and staying secure.
Also, dont let yourself to forget about diversification which is extremely important tool in any types of investments, that should be always your advantage that even when any asset price will go down, then you are still being covered by the other instruments.
So, why won't you choose bitcoin and gold? Both assets are simply great and you may get decent interest on holding both of them, so I cannot understand why you should choose one.
The gold is surely a great thing during crisis, or when people want to make their money safe: then they buy gold, what increases the price.