Can fractional shares mess up my dividends or voting rights?

Mostly no on dividends and partly yes on other features. If you own a fraction of a share, you generally still receive a proportional fraction of any dividend, so a half share pays half the dividend, often reinvested automatically. Voting rights and shareholder perks are where fractional ownership gets murky, since many brokerages don't pass through proxy voting for fractional positions, and rules vary by firm. Fractional shares can also complicate transferring your account to another brokerage, because fractions often must be sold rather than moved in kind, which can trigger a small taxable event in a taxable account. For a beginner steadily investing small amounts, these are minor tradeoffs. Just read your brokerage's fractional-share policy so you aren't surprised at tax time or when switching firms.