Is this a wash sale?

First in, first out (FIFO) is the default (oldest shares are sold first).

Last in, first out (LIFO) is the opposite. You sell your newest shares first.

If you use any method other than FIFO, you must tell your broker which shares you want sold. According to IRS Publication 550, the burden is on you to prove that you instructed your broker which shares to sell and that your broker followed your requests. If you can't prove that, you're treated as having sold your oldest shares first (FIFO).

If the shares purchased in January of 2018 were bought more than 30 days before the March sale then there is no wash sale. If that's the case then you could have designated that shares from the first purchase were sold (a loss) or shares from the second purchase were sold (a gain).

No because the trades are more than 30 days apart. If the spring sell trade were within 30 days of the winter buy trade, it would be a wash sale.

From Wikipedia:

Under Section 1091, a wash sale occurs when a taxpayer sells or trades stock or securities at a loss, and within 30 days before or after the sale:

Buys substantially identical stock or securities, Acquires substantially identical stock or securities in a fully taxable trade, Acquires a contract or option to buy substantially identical stock or securities, or Acquires substantially identical stock for an individual retirement account (IRA). The "substantially identical stock" acquired in any of these ways is called the "replacement stock" for that original position.

The above is not tax advice, please consult your tax professional for advice if trading.