Seven years seems a bit excessive. My own usually take about 4 years to first flowering. Ian Young's estimable advice on seed sowing should be available somewhere here if you search, but to summarise sow the seed with a little depth, vernalise over winter and with fresh seed you should see cotyledons in spring at about the time the mature bulbs emerge. Potting compost with a little extra sand works well for me. As with lily seedlings and the like keep them cool and well watered without waterlogging to keep them growing as long as possible. I've just been looking at a pot of 2nd year revolutum seedlings; most of the seedlings emerged the first spring, but a small proportion are only just appearing this year - so a little patience is useful.
