1. First step. Look up MtGox and what happened--that is the kind of risk you run with third parties holding your coin. However, Coinbase has a much better track record in many ways.

Ultimately you are still allowing a third party to hold your Bitcoin for you. Thus you are at their mercy if they go under in bankruptcy or if they mismanage your affairs. Long term you should consider understanding cold storage and / or hardware wallets to hold your money yourself.

1. Bitcoin is the granddaddy. I don't have enough experience to tell you predictions or general thoughts other than Bitcoin has been the king this far, and it's always good to diversify into healthy / legitimate options at your discretion.

2. Keep learning and never speculate (bitcoin is largely volatile and speculative still) with money you can't afford to lose entiretly.