You can be adventurous and start from SCRATCH, or you can get "starts" and play it safe. If you start from scratch you can use seeds and watch your plants grow from almost microscopic size all the way up to fruition. The difficult part of this is transferring the plant as it grows. You might want to start with a big container, so you wont have to transfer it so many times before it finally makes it into your garden. If you decide to go with "starts" (a lot of people do this, even seasoned gardeners use starts for finicky plants) you have the advantage of someone else doing a lot of the work for you.
But: Don't do what I did the first time.... I started about 100 plants in my kitchen (which isn't very big) and it was messy, and they were too early, so I had to start them AGAIN ! I'm in Washington and it is cold here and can freeze up into April sometimes. It did last year.
It was a learning experience and thank goodness seeds don't cost very much. I used mostly middle of the road (not too cheap or expensive) seeds and did just fine. I cheated on my tomatoes. A good freind of mine does all organic gardening, so I got my tomato starts from her. We had more tomatoes than we could eat.
Your garden may not come out right the first time. Big Deal ! Try and try again. I used a lot of the things I grew for my business. I did flowers and sold starts and small containers and even dried some. I also have begun to sell seeds I harvest from my garden. It was really nice to take a bag of vegetables to freinds who didn't have a garden also. If you haven't had fresh from the garden tomatoes, you have to try. They taste nothing like the store or street side market type. Delicious, Fresh and Healthy ! Not to mention saving money all summer. Make sure you check out your zone, and always follow directions on the seed packets. They are not all the same, and different vegetables start at different times.
Good luck ! Until next time ! Follow your heart !