Hi, a friend told me that this is the best time to start buying btc because it's price is dropping, but do you think i should wait and see if it keeps going down? I only have a small amount of money to invest. Thanks for your help, I'm new to this world
Oh my, define small amount

If your small amount is equivalent to just a few hundred bucks, then I will not suggest investing in Bitcoin. Instead you should go for Alt coins, there are lots of potential tokens with a good team and solid project which will only see multiple digits percentage increase of its value. Until you hold enough to convert some/most to Bitcoin, that is possibly the best alternative you have.
And bear in mind too, entering Crypto is just like entering any investment. If you do not do your own research you will not go far.