I'm 19 and I've recently started having sex. I was never interested in birth control because I was afraid I'd gain weight as it's very hard for me to lose weight. Now I'm considering birth control but my older sister told me that her birth control has delayed her from trying for another baby (yes, she's off of it already) because she isn't fertile enough due to being on birth control for five year (she took the Nuva Ring). Are there any birth controls that won't make me gain weight and won't make it difficult to conceive once I want children? I know I should talk to a gynecologist but our insurance hasn't given me the "ok" to go yet.