am i too big for a honda crf150f?

[Travis]

i bought this dirt bike cheap its a 2009 brand new practically but 1 its hard to pull wheelies and every video i see its a 15-16 year old kid riding it im 21 156lbs am i too big for this thing or am i just dumb? this is my first dirt bike my friend told me to get a 125cc but i think he meant a 2stroke mine is a 4. im just curious really i dont think but if i do take it somewhere i dont wanna be embarrassed for being a grown man on a kids bike. if theres any mods you would suggest to "beef" it up alittle to make it more powerful lemme know a site (preferably a link) thank you