Could be the same and most probably is since I have heard peopel who didn't know better call Jackmanii 'Jackman'. Posting a picture when it blooms will help confirm whether it is one and the same plant or not. As to how long it will take to mature, most clematis take ~3 years to get settled in and in full blooming form. Some make take less time and others may take longer depending on the cultivar. The size of the plant you purchased will also determine how long it takes to become a mature plant. A small liner plant will take far longer to get to maturity than a larger one, two or even three gallon plant will take.