It does seem a waste to get a shearer for three little sheep. As Kanisha says, they are primitives so will have a fleece rise which is so easy to cut through, or you can roo them ie gently pull the fleece off lock by lock, while bracing the skin with your other hand. You'll have them for many years, so it's worth doing it yourself. Just choose a nice sunny day, sit out in the sun and take your time, either hand shearing or roo'ing. There's no rush. Sometimes when you roo, only part of the fleece is ready to come off, so you leave the rest, usually in the form of 'pantaloons'
for another couple of weeks.
For fly strike, there is a danger period from May until they are ready to be shorn, but with only three you can keep a very close eye on them - backsides, under the tail, up in the crutch and behind the shoulders. Check them daily and at the very first signs of an egg or maggot problem, deal with it. The fleece can be sacrificed for the welfare of the sheep.