Even considering the current price of Bitcoin, buying a hundred dollars worth of Bitcoin is not a good decision. There is no apparent benefit of investing a 100 dollar in Bitcoin.Because investment in Bitcoin requires huge capital and you have less capital. It would have been nice if you had bought a small altcoin that was worth less than a dollar instead of investing in bitcoin. you would have received hundred of tokens for a hundred dollars that you could have profited from in the future. Because there are many good projects in the market that are currently priced at less than a dollar, And when the market goes up, there is a high chance that those small Altcoins can give you great profits. But for this it is important that you choose the best and top Altcoins.
Hundred dollar maybe not a decent amount in your currency, but 3rd word country like Nigeria I think that is where OP is from 100 dollars is a huge amount of money. Investing 100$ maybe not a moderate amount to invest in bitcoin but it is also not a bad amount to start with. I remember I only invested 20 dollars when I first started bitcoin trading, but also later that month I was able to invest more.
Altcoin investment is risky and suggesting someone new to invest in altcoin is also bad decision.