8 lessons ever? It might be too soon for you to be riding on your own if you've only had 8 lessons ever. If you've been riding in other disciplines, then it should be fine. Talk to your trainer. Consider what the terms of the lease are - would yo have to pay for board, vet, farrier? If so, then definitely hold off until you've got a stronger sense of what you want from riding. If your trainer feels you're OK to ride unsupervised and you're not going to have to pay for the upkeep, then I'd go for it.
Just remember that if you do end up leasing, that it's not your horse. If could end up being sold to someone else - so try not to fall in love :)