Dena,It's hard to identify what kind of lilac as there are so many cultivars with similar looking flower colours. One of the largest collections of lilacs is managed by the University of Guelph here in Ontario. Perhaps you can make your inquiries directly with their staff.

Here is a link that might be useful: Lilac arboretum in Guleph,

Thanks ianna :)

Judging by its leaves, it looks like Preston lilac. I have a white-flowering Preston lilac and just love it:
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It's possible you have the Preston lilac 'Nocturne'.

Here is a link that might be useful: Preston lilac 'Nocturne'

It looks like it could be Syringa pubescens, syn. S. microphylla, common name Lilac 'Sperba'.

Here is a link that might be useful: RHS

Thank you all for taking the time to answer my question, very helpful :). thanks again