It is possible. I did it. I took French 3 over the summer and moved right to French 4. (French is a passion of mine!) BUT, I did it with the help of my French teacher. We met once a week during summer for private lessons. She recognized my love for French, and gave me lessons on her own free time. She truly is a gem and a wonderful teacher. I also am one of those people who are good at learning languages, with a particularly keen ear for French.
Bon chance, mon ami!