[wchrisn]

Investing is about creating assets and having a diversity of assets. Assuming that $100/month is one part of your expendable income that you have considered for crytocurrency - you are in good hands. However if you are putting 100% of your expendable amount in cryptocurrency - do revisit other options.

Do also go through https://www.wealthfront.com/questions and other finance portals to see how they allocate your investments amount based on risk profile, age and goals.