My first impulse when I read your posting was to wonder how old you were and if you'd live to see a shrub grow to any substantial size from a seed.

Then I thought about the monstrous crabapple tree on my lawn that was 24 inches high and pencil diameter when I planted it in 1981 and the other assorted enormities around here that started in 2 inch peat pots.

I say go for it!

I hope to be around another 50 years or so. Hopefully, the lilacs will grow a bit in that time! People in other areas of GW seem to have been happy with starting them from seed so I'll try it out. My only problem is I hope I don't get bored with the lilacs after a few years in pots and just let them die!

It's a lot faster and easier just to dig up suckers from the base and start the that way. In early spring, dig out a sucker with a piece of root and just plant it where you want the bush to be. There's a reason that so many people have lilac hedges and it isn't from buying them at nurseries!
You can also grow them from cuttings taken now. Dip the end in rooting hormone and put in a pot of potting soil with a baggie over it or in good garden soil with a jar over it. Not in direct sun or you'll cook it.