Hello and welcome to the forum. It's good that you are seeking some advice before you get too far involved in bonsai. I agree with all the concerns/issues that Tom has mentioned. Here are a few more things to consider.
Bonsai from cuttings, or seed, is very long process that, while most definitely possible, is not the best approach for a beginner. It will take years of growth until you have something that resembles the trees you are seeing on-line or in books.
Whenever I start with such young material (usually seeds in my case) I always start as many as I can. The path from young plant to mature bonsai is fraught with many perils and by starting with only one there is a good chance that that particular individual will not make it to maturity.
Pines, in general, are difficult, they require a specific strategy that would not necessary if you were using deciduous material. Many deciduous species can be grown out, chopped back to the trunk and be expected to push new growth. Pines cannot be grown this way, therefore the grower must simultaneously develop the trunk while keeping a pathway open to later branch development.
White Pines, Pinus strobus
, would not be very high on most growers list of suitable material. There are much better choices among Pines, Japanese Black Pines for instance. Seeds for this species are readily available on line and could be ordered in time to get a good start next spring as Tom suggests.
If you must try Pines, seedlings are probably easier than cuttings. Although I have never tried Pine cuttings Dirr & Heuser state that:
"Pines as a group are very difficult to root from cuttings..."
Take a little time, step back and reevaluate your goals for bonsai. If you are intent upon growing temperate species, then this fall is not the correct season to do much other than perhaps acquire some stock. Often nurseries will offer material at a discount this time of year in order to be rid of it.
If you want something for the house you have more flexibility *
. With some forethought, and probably a modest cash outlay, you can start with one of the species that is more suited to indoor culture. Ficus is the most obvious choice here but there are many others.
Sorry if all of this sounds like we are discouraging you, that is not our intention. It is probably better that you get some of these missteps out the way early. On the plus side, you have not invested any cash or much time in this project so you have not really lost anything. Consider joining a local club where you will find a wealth of knowledge and people who will be willing to offer you their time and perhaps even some starter material.
Let me clarify that thought. I meant that at this time of year you will have more options indoors. This is because the season for outdoor work is winding down. Indoors, the season is much less of an issue.